1% checked with "ispell" sep.2003 /hjaaj
2% File: Sirius.tex
3
4\def\mxfelt{20 } % max number of finite fields
5
6
7\chapter{\label{chap:sirius-inpref}Molecular wave functions, {\sir}}
8
9\section{\label{sec:sirius-ref-notes} General notes for the {\sir} input reference
10manual}
11
12{\sir} is the part of the code that computes the wave function/density.
13
14The following sections contain a list of all generally relevant keywords to
15{\sir}, only currently inactive keywords and some special debug
16options are omitted.
17
18\begin{enumerate}
19\item {The input for the wave function section must begin with
20
21\begin{inputex} \begin{verbatim}
22**WAVE FUNCTIONS
23\end{verbatim} \end{inputex}
24   with no leading blanks.  The preceding lines in the input file may
25   contain arbitrary information.
26}
27
28\item{Input is directed by keywords which internally are stored
29   in upper case, however, in the input file they may be written in upper, lower, or mixed case.
30   Only the first 7 characters including the prompt are significant.
31   The keywords are divided in a number of main input groups. Each main
32   input group is initiated by a {\starkey}. For example
33
34\begin{inputex} \begin{verbatim}
35*ORBITAL INPUT
36\end{verbatim} \end{inputex}
37   marks the beginning of the input group for orbital input.
38}
39
40\item {The keywords belonging to one of the main input groups begin with
41   the prompt {\dotkey}.
42}
43
44\item {Keywords that are necessary to specify are marked by "Required".
45   For other keywords the default values can be used in ordinary runs.
46}
47
48\item {Any keyword line beginning with a \quotekw{!} or
49   \quotekw{\#} will be treated as a
50   comment line.  An illegal keyword will cause a dump of all keywords
51   for the current input section.
52}
53
54\item{A dump of keywords can be obtained in any input section by
55specifying the keyword \quotekw{\Key{OPTIONS}}.  For example, the input
56
57\begin{inputex} \begin{verbatim}
58**WAVE FUNCTIONS
59.OPTIONS
60**END OF DALTON INPUT
61\end{verbatim} \end{inputex}
62
63   will cause a dump  of all keywords in the main input groups in {\sir}, while
64
65\begin{inputex} \begin{verbatim}
66**Wave functions
67*Orbital input
68.options
69**End of Dalton input
70\end{verbatim} \end{inputex}
71
72   will cause a dump of all keywords in the \quotekw{*ORBITAL INPUT} input group
73   in {\sir} (this is also an example of using mixed case for the keywords).
74}
75
76\item{ The {\sir} input is finished with a line beginning with two stars {\starstarkey},
77   {\it e.g.}
78
79\begin{inputex} \begin{verbatim}
80**END OF DALTON INPUT
81\end{verbatim} \end{inputex}
82   or {\it e.g.}
83
84\begin{inputex} \begin{verbatim}
85**Properties
86\end{verbatim} \end{inputex}
87
88}
89\end{enumerate}
90
91\pagebreak[3]
92\section{\label{sec:ref-newinp}
93   Main input groups in the **WAVE FUNCTIONS input module}
94
95\noindent
96The main input groups (those with the {\starkey} prompt) are listed here and
97the full descriptions are given in the designated sections.
98
99\noindent
100The first input group is always required in order to specify the type of
101calculation, and follows immediately after the \Sec{*WAVE FUNCTIONS}
102keyword.
103
104%Section~\ref{ref-geninp} \Sec{GENERAL INPUT}
105
106\noindent The remaining input groups may be specified in any
107order. In this chapter they are grouped alphabetically, although
108the short presentation below gather them according to purpose.
109
110%\ifsolvent
111The following two input groups are used to modify the
112molecular environment by adding field-dependent
113terms in the Hamiltonian and by invoking
114the self-consistent reaction field model for solvent
115effects, respectively:
116
117Section~\ref{ref-haminp} \Sec{HAMILTONIAN}
118
119Section~\ref{ref-solinp} \Sec{SOLVENT}
120%\else
121%The following input group describes additional field-dependent
122%terms in the Hamiltonian :
123%
124%Section~\ref{ref-haminp} \Sec{HAMILTONIAN}
125%\fi
126
127\noindent
128The next input group specifies the configurations included
129in the MCSCF, MC--srDFT, CI, and CI--srDFT wave functions:
130
131Section~\ref{ref-wavinp} \Sec{CONFIGURATION INPUT}
132
133\noindent
134The two next groups are used to specify initial orbitals and initial
135guess for the CI vector:
136
137Section~\ref{ref-orbinp} \Sec{ORBITAL INPUT}
138
139Section~\ref{ref-civinp} \Sec{CI VECTOR}
140
141\noindent
142The two following input groups control a second-order MCSCF, MC--srDFT, HF, HF-srDFT, or DFT
143optimization:
144
145Section~\ref{ref-optinp} \Sec{OPTIMIZATION}
146
147Section~\ref{ref-stpinp} \Sec{STEP CONTROL}
148
149\noindent
150The next groups have special input only relevant for the
151specified calculation types:
152
153Section~\ref{ref-rhfinp} \Sec{SCF INPUT}, for \Key{HF}, \Key{DFT}, and \Key{HFsrDFT}
154
155Section~\ref{ref-dftinp} \Sec{DFT INPUT}, for \Key{DFT}
156
157Section~\ref{ref-mp2inp} \Sec{MP2 INPUT}, for \Key{MP2} or \Key{MP2SRDFT}
158
159Section~\ref{ref-nevpt2inp} \Sec{NEVPT2 INPUT}, for \Key{NEVPT2}
160
161Section~\ref{ref-cicinp} \Sec{CI INPUT}, for \Key{CI}
162
163Section~\ref{ref-stexinp} \Sec{STEX INPUT}, for \Key{STEX}
164
165\noindent
166The next section is used to select some types of analysis of the final
167HF, HF-srDFT, DFT, MCSCF, MC--srDFT, CI, or CI--srDFT wave function:
168
169Section~\ref{ref-popinp} \Sec{POPULATION ANALYSIS}
170
171\noindent
172The next section is used to change the default integral transformation
173and specify any final integral transformation after convergence (a
174main Dalton module following {\sir} may need a higher transformation level):
175
176Section~\ref{ref-trainp} \Sec{TRANSFORMATION}
177
178\noindent
179The next two input groups control the amount of printed output and
180collect options not fitting in any of the other groups:
181
182Section~\ref{ref-priinp} \Sec{PRINT LEVELS}
183
184Section~\ref{ref-auxinp} \Sec{AUXILIARY INPUT}
185
186\noindent
187Finally we note that there is an input module controlling the
188calculation of coupled cluster wave functions. This is treated in a
189separate chapter:
190
191Chapter~\ref{ch:CC} \Sec{CC INPUT}
192
193\bigskip
194\noindent
195The wave function input is finished when a line is encountered beginning
196with two stars {\starstarkey}, two examples:
197
198\begin{inputex} \begin{verbatim}
199   **END OF DALTON INPUT
200\end{verbatim} \end{inputex}
201and
202
203\begin{inputex} \begin{verbatim}
204   **MOLORB
205   ... formatted molecular orbitals coefficients
206   **END OF DALTON INPUT
207\end{verbatim} \end{inputex}
208
209\noindent
210The \Sec{*MOLORB} keyword or the \Sec{*NATORB} keyword
211must be somewhere on the input file and be
212followed by molecular orbital coefficients if the option for formatted
213input of molecular orbitals has been specified.  Apart from this
214requirement, arbitrary information can be written to the following lines
215of the input file.
216
217
218
219\pagebreak[3]
220\subsection{\label{ref-geninp}\Sec{*WAVE FUNCTIONS}}
221
222{\bf Purpose:}
223
224Specification of which wave function calculation is to be performed.
225
226{\bf Primary keywords, {\color{red} listed in the order the corresponding modules
227 will be executed by the program (if the keyword is set)}: }
228
229\begin{description}
230
231\item[{\color{blue}Single configuration models}] Models with a single configuration SCF (HF, DFT, or HFsrDFT)
232
233\begin{description}
234
235\item[\Key{HF}]
236  Restricted closed-shell, one open-shell, or high-spin spin-restricted Hartree--Fock calculation.
237  \index{HF}\index{SCF}\index{Hartree--Fock}\index{open shell!HF}\index{high spin!HF}
238  (Unrestricted HF is not possible in \dalton.)
239  The occupied orbitals, optimization control etc. are specified in the
240  \quotekw{*SCF INPUT} submodule. \\
241  Note: you can only specify one of the \quotekw{.HF}, \quotekw{.DFT}, and \quotekw{.HFsrDFT} keywords.
242
243\item[\Key{HFsrDFT}]
244  Long-range Hartree-Fock  and short-range DFT (HF-srDFT) calculation. \index{HF-srDFT}
245  (Unrestricted HF-srDFT is not possible in \dalton.)
246  The short-range srDFT functional must be defined with the \quotekw{.SRFUN} keyword in this input section.
247  The occupied orbitals, optimization control etc. are specified in the
248  \quotekw{*SCF INPUT} submodule. \\
249  Default range-separation is the error function with $\mu = 0.4$, our standard value.
250  The value can be canged with the \quotekw{.ERF} keyword. \\
251  This option is quite similar to long-range corrected Kohn-Sham functionals, the only difference
252  is that long-range correction is also performed on the correlation funtional.
253  HF-srDFT with srPBEGWS may therefore be expected to give results close to LC-PBE.
254  Note: you can only specify one of the \quotekw{.HF}, \quotekw{.DFT}, and \quotekw{.HFsrDFT} keywords.
255
256\item[\Key{DFT}] \ \\
257  \kw{READ (LUINP,'(A80)') LINE} \\
258  Restricted closed-shell, one open-shell, or high-spin spin-restricted Kohn-Sham density functional
259  theory\index{DFT}\index{Kohn--Sham}\index{open shell!DFT}\index{high spin!DFT}
260  (Unrestricted Kohn-Sham DFT is not possible in \dalton.)
261  calculation.  On the following line you must specify which
262  functional to use.  The occupied orbitals, optimization control
263  etc. are specified in the \quotekw{*SCF INPUT} submodule shared with
264  the \quotekw{.HF} option. The DFT specific input options are
265  collected in the \quotekw{*DFT INPUT} input submodule.
266  Note: you can only specify one of the \quotekw{.HF}, \quotekw{.DFT}, and \quotekw{.HFsrDFT} keywords.
267
268\item[\quotekw{.FC MVO} in \quotekw{*SCF INPUT}]
269  Calculation of modified virtual SCF orbitals after SCF convergence based on the
270  potential determined by the keyword (see comments below).
271  The occupied SCF orbitals are not modified.
272  MVOs are typically used for subsequent CI calculation.
273  {\em Note that this keyword is not located in this module but in the
274  \quotekw{*SCF INPUT} submodule. It is mentioned here to make clear
275  at what point this orbital transformation will be performed, if requested.}
276  Option is incompatible with CC, which requires canonical orbitals.
277
278\item[\Key{SRFUN}] \ \\
279  \kw{READ (LUINP,'(A80)') LINE} \\
280  Specification of functional used for \quotekw{.HFSRDFT}, \quotekw{.MP2SRDFT}, \quotekw{.CISRDFT},
281  and \quotekw{.MCSRDFT} calculations. It is \emph{required} for these calculations, there is not default functional.
282  \index{Short-range functionals!.SRFUN}
283  Note that this keyword must not be specified together with the Kohn--Shan DFT keyword \quotekw{.DFT}.
284
285\item[\Key{HFXFAC}] \ \\
286  \kw{READ (LUINP,'(A80)') LINE} \\
287  Specification of the full-range Hartree-Fock like exchange for \quotekw{.HFSRDFT} and \quotekw{.MCSRDFT} calculations.
288
289\item[\Key{STEX}]
290  Static exchange calculation based on an SCF wave function.\index{Static exchange}
291
292\end{description}
293
294\item[{\color{blue} Single configuration based correlation models}] Models based on a single configuration (e.g.\ MP2, CC, and CI with orbitals from a single determinant calculation).
295
296\begin{description}
297
298\item[\Key{MP2}]
299 \index{M{\o}ller-Plesset!second-order, MP2}\
300  M{\o}ller-Plesset second-order perturbation theory calculation,
301  based on canoncial orbitals from an HF calculation calculation.
302  Calculates second-order energy, second-order natural orbitals\index{natural orbitals!MP2},
303  and first-order wave function for SOPPA.
304  Requires \quotekw{.HF} or previously calculated canonical HF orbitals.
305
306\item[\Key{MP2srDFT}]
307 \index{M{\o}ller-Plesset!MP2--srDFT}\
308  M{\o}ller-Plesset second-order perturbation theory calculation with short-range srDFT functionals,
309  based on canoncial orbitals from an HFsrDFT calculation.
310  Calculates second-order energy, second-order natural orbitals\index{natural orbitals!MP2--srDFT},
311  and first-order wave function for SOPPA--srDFT.
312  Requires \quotekw{.HFsrDFT}
313  or previously calculated canonical HF-srDFT orbitals.
314
315\item[\Key{CC}]
316  \index{Coupled Cluster!CC}
317  Coupled cluster calculation. Automatically activates Hartree--Fock (\quotekw{.HF}).
318  After the Hartree--Fock calculation,
319  the \cc\ module is called to do a coupled cluster (response) calculation.
320  M
321  For further input options for the \cc\ module see Section~\ref{sec:ccgeneral}.
322
323\item[\Key{CC ONLY}] Skip the calculation of a Hartree--Fock wave
324  function, and start directly in the coupled cluster part. Convenient
325  for restarts in the coupled cluster module.
326
327\end{description}
328
329\item[{\color{blue} Multi-configuration models}] CI, MCSCF, NEVPT2, GAS-CI; CI--srDFT, MC--srDFT, srNEVPT2.
330
331\begin{description}
332
333\item[\Key{CI}]
334  \index{Configuration Interaction!CI}
335  Configuration interaction calculation.
336  This CI will be based on the molecular orbitals from one of the SCF options, or
337  read in from file (then they can be from MCSCF, MP2, ...).
338
339\item[\Key{CIsrDFT}]
340  \index{CI--srDFT}\index{Configuration Interaction!CI--srDFT}
341  Long range configuration interaction and short-range DFT (CI--srDFT) calculation.
342  The short-range srDFT functional must be defined with the \quotekw{.SRFUN} keyword in this input section.
343  This CI--srDFT will be based on the molecular orbitals from one of the SCF options, or
344  read in from file (then they can be from MCsrDFT, MP2-srDFT, or in fact also from MCSCF, MP2, ...).
345  Note: you can only specify one of the \quotekw{.CI} and \quotekw{.CIsrDFT} keywords.
346
347\item[\Key{MCSCF}]
348  Multiconfiguration self-consistent field (MCSCF) calculation. CASSCF or RASSCF .\index{MCSCF}\\
349  It is in most cases recommended that you use initial orbitals from MP2 for faster convergence to
350  the desired state (other initial guesses more often end in a local minimum).
351  For open-shell states not well described with MP2 you may consider using the \quotekw{.CINO} option for initial orbitals.\\
352  Note: you can only specify one of the \quotekw{.MCSCF} and \quotekw{.MCsrDFT} keywords.
353
354\item[\Key{MCsrDFT}]
355  Long-range MCSCF and short-range DFT (MC--srDFT) calculation. CAS-srDFT or RAS-srDFT.\index{MC--srDFT}
356  The short-range srDFT functional must be defined with the \quotekw{.SRFUN} keyword in this input section.
357  Default range-separation is the error function with $\mu = 0.4$, our standard value.
358  The value can be canged with the \quotekw{.ERF} keyword. \\
359  It is normally recommended that you use initial orbitals from MP2-srDFT for faster convergence to
360  the desired state (other initial guesses more often end in a local minimum). \\
361  Note: you can only specify one of the \quotekw{.MCSCF} and \quotekw{.MCsrDFT} keywords.
362
363\item[\Key{VIRTRUNC}] \ \\
364  \kw{READ (LUINP,*) N, THR\_VIRTUNC} \\
365  Truncate virtual space after SCF or MCSCF, write reduced orbital information to
366  "\verb|SIRIUS.RST|" and stop \dalton. Start a new \dalton\ calculation with the
367  reduced set of molecular orbitals using ".MOSTART NEWORB" and, if MCSCF, ".STARTOLDCI"
368  in the relevant input sections (the ".RESTART" option cannot be used).
369  In input N is either 2 or 4, and all virtual orbitals with eigenvalues of
370  $r^N$ greater than ( THR\_VIRTRUNC )$^N$ are deleted.
371  The THR\_VIRTRUNC is thus a measure of the maximum extent (diffuseness) of a virtual orbital.
372  All the occupied orbitals are not modified.
373
374\item[\Key{NEVPT2}]
375  Multireference second-order perturbation theory calculation.\index{NEVPT2}
376  Requires preceding MCSCF or MC--srDFT calculation.
377
378\end{description}
379
380\end{description}
381
382{\bf Secondary keywords (in alphabetical order): }
383
384\begin{description}
385
386\item[\Key{ERF}] \ \\
387  \kw{READ (LUINP,*) new\_mu\_value} \\
388  Default range-separation for all srDFT modelse is the error function with $\mu = 0.4$, our standard value.
389  With this option you can change the $\mu$ as desired.
390
391\item[\Key{FLAGS}] \ \\
392  \kw{READ (LUINP,NMLSIR)} \\
393  Read namelist "NMLSIR". Example: \verb" $NMLSIR NPATH=3,5,-7, $END" \\
394  Set internal flags no. 3 and 5 to true and flag no. 7 to false.
395  Only for debugging. Set internal control flags directly.
396  For example  \verb" &NMLSIR NPATH=61,-43,  &END" sets flag(61) true and flag(43) false.
397  Usage is not further documented.
398
399\item[\Key{INTERFACE}]
400  Write the "\verb|SIRIFC|" interface file\index{interface file} for post-processing programs.
401
402%hjaaj oct 2003: obsolete ...
403%\item[\Key{NSYM}]
404%%  Required, no defaults. \\
405%  Default: specified by integral program \\
406%  \verb"READ (LUINP,*) NSYM" \\
407%  Number of spatial Abelian symmetries (1, 2, 4, or 8), corresponding
408%  to $D_{2h}$ or one of its subgroups.
409
410\item[\Key{PRINT}] \ \\
411  \kw{READ (LUINP,*) IPRSIR} \\
412  General {\sir} print level and default for all other print parameters in this module
413  (default is the general print level from \verb|**DALTON|).
414
415\item[\Key{RESTART}]
416  Restart {\sir}\index{restart!wave function} second order optimization of HF, HF-srDFT, MCSCF, or MC--srDFT.
417  The {\sir} restart file (\verb|SIRIUS.RST|) must be available and contain restart information.
418
419%hjaaj Oct 2003: obsolete, we want the specific .HF or .DFT
420%\item[\Key{SCF}]
421%    Alias for the \quotekw{\Key{HF}} keyword.
422
423\item[\Key{STOP}] \ \\
424  \kw{READ (LUINP,'(A20)') REWORD} \\
425  Terminate {\sir} according to the instruction given on the following line.
426  Three stop points are defined:
427\begin{enumerate}
428
429\item \hspace{2em} \quotekw{ AFTER INPUT}
430
431\item \hspace{2em} \quotekw{ AFTER MO-ORTHONORMALIZATION}
432
433\item \hspace{2em} \quotekw{ AFTER GRADIENT} (only for MCSCF and 2nd-order HF or DFT)
434\end{enumerate}
435
436\item[\Key{TITLE}]  \ \\
437  \kw{READ (LUINP,'(A)') TITLE(NTIT)} \ \\
438  Any number of title lines (until next line beginning with a
439  \quotekw{.} or \quotekw{*} prompt).
440  Up to 6 title lines will be saved and used in the output, additional
441  lines will be discarded.
442
443\item[\Key{WESTA}]
444  Write the file "\verb|SIRIUS.STRINGINFO|" with CI string information for the WESTA post-processing program.
445
446%hjaaj Oct 2003: obsolete
447%\item[\Key{BASIS SET}]
448%   Default: specified by integral program \\
449%   \verb"READ (LUINP,*) (NBAS(I), I = 1,NSYM)" \\
450%   Number of basis functions per symmetry.
451\end{description}
452
453%hj%\noindent{\bf Comments:}
454
455%\ifabacus ABACUS:
456%If the full molecular Hessian is calculated in
457%ABACUS and the number of symmetries (\verb|NSYM|) is greater than
458%one, then the MCSCF wave function will be automatically calculated
459%in determinants\index{determinants} and, if singlet,
460%\quotekw{.PLUS COMBINATIONS}).  This is so because the CSFs can
461%only have one spatial symmetry, and it is generally necessary to
462%solve linear response equations of several symmetries to get the
463%full molecular Hessian.
464%\fi
465
466%hjaaj Oct 2003: obsolete
467%BASIS SET is provided such that the number of basis functions in each
468%symmetry may be specified if {\sir} is modified to interface to an
469%integral program which doesn't write this information to the integral
470%file.
471
472\pagebreak[3]
473\subsection{\label{ref-auxinp}\Sec{AUXILIARY INPUT}}
474
475{\bf Purpose:}
476
477Input which does not naturally fit into any of the other
478categories.
479
480\begin{description}
481\item[\Key{NOSUPMAT}]
482  Do not use P-SUPERMATRIX integrals, but calculate Fock matrices
483  from AO integrals (slower, but requires less disk space). The
484  default is to use the supermatrix file if it exists. See option
485  \Key{NOSUP} in Chapter~\ref{sec:herminp}.
486
487%\item[\Key{ONESUP}]
488%  Use same unit for P-SUPERMATRIX\index{supermatrix} and ONE-ELECTRON
489%  integrals \index{one-electron integral}
490%  (LUSUPM=LUONEL, default is different units).
491\end{description}
492
493\pagebreak[3]
494\subsection{\label{ref-cicinp}\Sec{CI INPUT}}
495
496{\bf Purpose:}
497
498Options for a CI calculation.
499
500\begin{description}
501\item[\Key{CIDENSITY}]
502  Calculate CI one-electron density matrix and natural
503  orbital\index{natural orbitals!CI}
504  occupations after convergence.
505
506\item[\Key{CINO}]
507  Generate CI\index{CI}\index{Configuration Interaction} natural
508  orbitals\index{natural orbitals!CINO} for CI root
509  number \kw{ISTACI},
510  clear the \verb|SIRIUS.RST| file and write the orbitals with label \quotekw{NEWORB  }.
511  The \quotekw{\Key{STATE}} option must be specified.
512
513\item[\Key{CIROOTS}]
514  Default: One root.\\
515  \kw{READ (LUINP,*) NROOCI} \\
516  Converge the lowest \kw{NROOCI} CI roots\index{root!CI} to threshold.
517
518\item[\Key{DISKH2}]
519  Active two-electron MO integrals on disk (see comments below).
520
521\item[\Key{MAX ITERATIONS}] \ \\
522  \kw{READ (LUINP,*) MXCIMA} \\
523  Max iterations in iterative diagonalization of CI matrix (default = 25).
524
525\item[\Key{STATE}]
526  Default: not specified\\
527  \kw{READ (LUINP,*) ISTACI} \\
528  Alternative to \quotekw{\Key{CIROOTS}}.  Converge root number \kw{ISTACI}
529  to threshold, converge all lower roots only to THQMIN
530  (from the \quotekw{\Sec{OPTIMIZATION}} input group, see
531  p.~\pageref{ref-optinp}).
532
533\item[\Key{THRESH}]
534  Default = 1.D-05\\
535  \kw{READ (LUINP,*) THRCI} \\
536  Threshold for CI energy gradient.  The CI energy will be converged to
537  approximately the square of this number.
538
539\item[\Key{THRPWF}]
540  Default is 0.05 for electronic ground states, and 0.10 for excited states.\\
541  \kw{READ (LUINP,*) THRPWF} \\
542  Only CI coefficients of absolut value greater than threshold are printed
543  (PWF: print wave function).
544
545\item[\Key{WEIGHTED RESIDUALS}]
546  Use energy weighted residuals\index{residual} (see comments below).
547
548\item[\Key{ZEROELEMENTS}]
549  Zero small elements in CI trial vectors (see comments below).
550\end{description}
551
552
553\noindent{\bf Comments:}
554
555DISKH2: By default the CI module will attempt to place the two-electron
556integrals with four active indices in memory for more efficient
557calculation of CI sigma vectors, if memory is insufficient for this
558the
559integrals will automatically be placed on disk.  The DISKH2 keyword
560forces the integrals always to be on disk.
561
562WEIGHTED RESIDUALS:  Normally the CI states will be converged to a
563residual less than the specified threshold, and this will give
564approximately the squared number of decimal places in the energy.
565Depending on the value of the energy, the eigenvectors will be converged
566to different accuracy. If the eigenvectors are wanted with, for instance at
567least 6 decimal places for property calculations, specify a threshold of
5681.0D-6 and weighted residuals.
569
570ZEROELEMENTS: an experimental option that might save time (if the CI
571module can use sparseness) by zeroing all elements less than 1.0D-3
572times the largest element in the CI trial vector before
573orthonormalization against previous trial vectors.
574See also \quotekw{.SYM CHECK} under \quotekw{*OPTIMIZATION}
575(p.~\pageref{ref-optinp}).
576
577
578\pagebreak[3]
579\subsection{\label{ref-civinp}\Sec{CI VECTOR}}
580
581{\bf Purpose:}
582
583To obtain initial guess for CI vector(s).
584
585\begin{description}
586\item[\Key{PLUS COMBINATIONS}]
587  Use with \quotekw{\Key{STARTHDIAGONAL}} to choose plus combination
588  of degenerate   diagonal elements ({\bf STRONGLY RECOMMENDED} for
589  calculation of singlet states  with \quotekw{\Key{DETERMINANTS}}).
590
591\item[\Key{SELECT}] \ \\
592  \kw{READ (LUINP,*) ICONF} \\
593  Select CSF (or determinant if \quotekw{\Key{DETERMINANTS}}) no.
594  ICONF as start configuration.\index{configuration!start}
595
596\item[\Key{STARTHDIAGONAL}]
597  Select configurations corresponding to the lowest diagonal elements in
598  the configuration part of the Hessian (this is the default option).
599
600\item[\Key{STARTOLDCI}]
601  Start from old CI-vector stored saved on the \verb|SIRIUS.RST| file.
602
603%\ifabacus
604%\item[.ABACUS]
605%  Geometry walk, use CI vector and "GEOSAVE" information saved by
606%  ABACUS at previous geometry.  The "GEOSAVE" information is used
607%  to decide as early as possible in the wave function optimization
608%  if the step should be rejected, thus saving CPU time if the step
609%  is rejected.
610%\fi
611
612\end{description}
613
614\pagebreak[3]
615\subsection{\label{ref-wavinp}\Sec{CONFIGURATION INPUT}}
616
617{\bf Purpose:}
618
619To specify the configuration part in .MCSCF and .CI calculations.
620
621\begin{description}
622\item[\Key{CAS SPACE}] \ \\
623  \kw{READ (LUINP,*) (NASH(I),I=1,NSYM)} \\
624  CAS calculation: Active orbitals\index{active orbital} in each symmetry.
625
626\item[\Key{ELECTRONS}]
627  Required.\\
628  \kw{READ (LUINP,*) NACTEL} \\
629  Number of active electrons\index{active electrons} (the number of
630  electrons to be distributed in the active orbitals).
631  The total number of electrons is this number
632  plus two times the total number of inactive orbitals.
633
634\item[\Key{INACTIVE ORBITALS}]
635  Required.\\
636  \kw{READ (LUINP,*) (NISH(I),I=1,NSYM)} \\
637  Number of inactive orbitals\index{inactive orbital} each symmetry.
638
639\item[\Key{RAS1 ELECTRONS}] \ \\
640   \kw{READ (LUINP,*) NEL1MN,NEL1MX} \\
641   Minimum and maximum number of RAS1 electrons; this can alternatively
642   be specified with \quotekw{\Key{RAS1 HOLES}}
643
644\item[\Key{RAS1 HOLES}] \ \\
645  \kw{READ (LUINP,*) NHL1MN,NHL1MX} \\
646  Minimum and maximum number of holes\index{electron hole} in RAS1; alternative
647  to \quotekw{\Key{RAS1 ELECTRONS}}
648
649\item[\Key{RAS1 SPACE}] \ \\
650   \kw{READ (LUINP,*) (NAS1(I),I=1,NSYM)} \\
651   RAS calculation: RAS1 orbital space\index{RAS1 orbital space}
652
653\item[\Key{RAS2 SPACE}] \ \\
654   \kw{READ (LUINP,*) (NAS2(I),I=1,NSYM)} \\
655   RAS calculation: RAS2 orbital space\index{RAS2 orbital space}
656
657\item[\Key{RAS3 ELECTRONS}] \ \\
658   \kw{READ (LUINP,*) NEL3MN, NEL3MX} \\
659   Minimum and maximum number of RAS3 electrons
660
661\item[\Key{RAS3 SPACE}] \ \\
662   \kw{READ (LUINP,*) (NAS3(I),I=1,NSYM)} \\
663   RAS calculation: RAS3 orbital space\index{RAS3 orbital space}
664
665\item[\Key{SPIN MULTIPLICITY}]
666  Default is 1 for even number of electrons, 2 for odd number of electrons. \\
667  \kw{READ (LUINP,*) ISPIN}\\
668  For CSF basis: state spin multiplicity\index{spin multiplicity} = $2S + 1$,
669  where $S$ is the spin quantum number. \\
670  For determinant basis this option determines the minimum spin
671  multiplicity.  The $M_S$ value is determined as (ISPIN-1)/2.
672
673\item[\Key{MS2}]
674  Default is determind by \kw{.SPIN MULTIPLICITY}. \\
675  \kw{READ (LUINP,*) MS2}\\
676  For CSF basis: MS2 specifies non-default $2 M_S$ value to be used in the determinant expansion of the CSFs.
677  The computationally optional MS2 value for, say, triplet is zero (default), but if you want to calculate
678  spin-density you should select MS2=2.\\
679  For determinant basis this option should never be used, if used it must give the
680  same $M_S$ value as the \kw{.SPIN MULTIPLICTY} key word.
681
682\item[\Key{SYMMETRY}]
683  Default is 1 (totally symmetric irrep).\\
684  \kw{READ (LUINP,*) LSYM} \\
685  Spatial symmetry\index{symmetry} of CI and/or MCSCF wave function.
686
687\end{description}
688
689\noindent{\bf Comments:}
690
691\noindent SYMMETRY   Specifies total spatial symmetry of the wave
692function in $D_{2h}$ symmetry or one of its subgroups: $C_{2v}$, $C_2h$,
693$D_2$, $C_s$, $C_i$, $C_2$, $C_1$. The  symmetry number of wave
694function follows MOLECULE output ordering of symmetries ($D_{2h}$
695subgroup irreps).
696
697\noindent
698CAS and RAS\index{RASSCF}\index{CASSCF}\index{MCSCF} are exclusive and
699both cannot be specified in the same
700MCSCF or CI\index{MCSCF}\index{CI}\index{Configuration Interaction}
701calculation. One of them {\em must} be specified.
702
703\pagebreak[3]
704\subsection{\label{ref-dftinp}\Sec{DFT INPUT}}
705
706{\bf Purpose:}
707
708To specify the parameters of the DFT integration and the optional use of empirical corrections.
709
710\begin{description}
711
712\item[\Key{DFTAC}] \ \\
713  \kw{READ (LUINP,*) RTYPE} \\
714  \kw{READ (LUINP,*) CTYPE} \\
715  \kw{READ (LUINP,*) DFTIPTA, DFTIPTB, DFTBR1, DFTBR2} \\
716  Switches on the asymptotic correction of the exchange correlation potential. This correction is a pointwise manipulation of the
717  exchange--correlation potential. This implies activation of the .DFTVXC keyword in the SCF stage. RTYPE defines the
718  potential to be used to replace the asymptotic GGA potential, possible options are MULTPOLE (a simple multipole model)
719  and LB94 (the potential from the LB94 model potential~\cite{dft:lb94}). CTYPE defines how the potential of the parent
720  functional is connected to the asymptotic model, possible options are LINEAR (as used in the Tozer-Handy correction~\cite{dft:th}),
721  TANH (a modified connection by Tozer~\cite{dft:tanh}, which removes discontinuities associated with linear interpolation) and
722  GRAC (the gradient-regulated asymptotic correction of Gr\"uning \emph{et. al.}~\cite{dft:grac}).  \\
723  Four numerical input parameters are then input
724  the first two are the $\alpha$ and $\beta$ ionization potentials (either calculated or experimental). If GRAC is chosen for the
725  connection type then the last two value specify the parameters $\alpha$ and $\beta$ (see Ref.~\cite{dft:grac} for details).
726  Recommended values are 0.5 and 40.0. Otherwise the last two parameters specify multiples of the
727  Bragg Radii and are used to define the core, interpolation and asymptotic regions. For grid points within DFTBR1 Bragg Radii of
728  each atom the potential is unmodified, for points outside DFTBR2 Bragg Radii the potential is replaced with its asymptotic model.
729  In between the interpolation model is used. Recommended values in this case are 3.5 and 4.7. Care should be taken when
730  choosing alternative values for the final two parameters in each scheme, inappropriate values can make SCF convergence difficult.
731
732
733\item[\Key{DFTD2}]
734  switches on Grimme's DFT-D2 empirical dispersion correction~\cite{dft:dftd2}.
735  The code will attempt to assign the correct functional dependent
736  parameters based on the chosen DFT functional. Analytic gradient contributions are available.
737
738\item[\Key{D2PAR}] \ \\
739  \kw{READ (LUINP,*) D2\_s6\_inp, D2\_alp\_inp, D2\_rs6\_inp} \\
740  using this keyword user input values of the $s_6$, $\alpha$ and $s_{r,6}$ DFT-D2 parameters may be specified. If supplied these values override
741  any values defined within the code.
742
743\item[\Key{DFTD3}]
744  switches on Grimme's DFT-D3 empirical dispersion correction~\cite{dft:dftd3}. The code will attempt to assign the correct functional dependent
745  parameters based on the chosen DFT functional. Analytic gradient contributions are available.
746
747\item[\Key{DFD3BJ}]
748  switches on Grimme's DFT-D3 empirical dispersion correction with Becke-Johnson damping~\cite{dft:dftd3bj}.
749  The code will attempt to assign the correct functional dependent parameters based on the chosen DFT functional.
750  Analytic gradient contributions are available. This is the presently recommended version.
751
752\item[\Key{3BODY}]
753  keyword for adding 3-body terms to the DFT-D3 dispersion energy. Note that gradients are not implemented for these corrections
754
755\item[\Key{D3PAR}] \ \\
756  \kw{READ (LUINP,*) D3\_s6\_inp, D3\_alp\_inp, D3\_rs6\_inp, D3\_rs18\_inp, D3\_s18\_inp} \\
757  keyword for specifying the $s_6$, $\alpha$, $s_{r,6}$, $s_{r,8}$ and $s_8$ parameters of the DFT-D3 methods. Note, take care to
758  match the parameter values to the correct version of the DFT-D3 correction.
759
760\item[\Key{DFTELS}] \ \\
761  \kw{READ (LUINP,*) DFTELS} \\
762  safety threshold -- stop if the charge integration gives too large
763  error.
764
765\item[\Key{DFTTHR}] \ \\
766  \kw{READ (LUINP,*) DFTHRO, DFTHRI} \\
767  Thresholds determining accuracy of the numerical integration. The
768  first number determines the density threshold (contributions to a
769  property from places where the density is below the threshold will
770  be skipped) and the second one -- orbital threshold (orbitals are
771  assumed to be exactly 0 if they are below the threshold). The
772  default value for DFTHR0 is $1.0D-9$ and for DFTRHI is $1.0D-13$.
773
774\item[\Key{DFTVXC}]
775  keyword to specify explicit construction of the exchange--correlation
776  potential for GGA forms. This is automatically invoked when .DFTAC is selected
777  and not recommended for use otherwise.
778
779\item[\Key{RADINT}] \ \\
780  \kw{READ (LUINP,*) RADINT} \\
781  Determines the quality of the radial part of the grid and
782  corresponds to the upper limit of the error in case of an
783  integration on an atom. Default value is $1.0D-13$.
784
785\item[\Key{ANGINT}] \ \\
786  \kw{READ (LUINP,*) ANGINT} \\
787  Determines the quality of the angular Lebedev grid -- the angular
788  integration of spherical harmonics will be exact up to the specified
789  order. Default value is 35.
790
791\item[\Key{GRID TYPE}] \ \\
792  \kw{READ (LUINP,*) LINE} \\
793  Allows specification of different partitioning methods and radial
794  schemes. \verb|BECKE| is Becke partitioning scheme with correction
795  for atomic sizes using Bragg sizes, \verb|BECKEORIG| is the same
796  Becke partitioning scheme but without correction. \verb|SSF| is a
797  partitioning scheme for large molecules designed to reduce the grid
798  generation time. \verb|LMG| select LMG radial scheme adjusted to
799  currently used basis set. Gauss-Chebychev radial scheme of second
800  order is provided for reference and can be selected by keyword
801  \verb|GC2|.
802
803% The default is \verb|BECKE LMG| which is optimal for an
804%  overwhelming number of cases.
805\item[\Key{COARSE}]
806  Shortcut keyword for radial integration accuracy $10^{-11}$ and
807  angular expansion order equal to $35$.
808\item[\Key{NORMAL}]
809  Default. Shortcut keyword for radial integration accuracy $10^{-13}$ and
810  angular expansion order equal to $35$.
811\item[\Key{FINE}]
812  Shortcut keyword for radial integration accuracy $10^{-13}$ and
813  angular expansion order equal to $42$.
814\item[\Key{ULTRAF}]
815  Shortcut keyword for radial integration accuracy $10^{-15}$ and
816  angular expansion order equal to $65$.
817
818\end{description}
819
820\subsection{\label{ref-dft}Kohn--Sham DFT functionals}
821
822In general, functionals in \dalton\ can be divided into two groups:
823generic exchange and correlation functionals
824and combined functionals. Combined functionals are a linear combination of
825generic ones. There are a large number of combined functionals defined below,
826however the user can also create their own combined functionals with
827the \verb|Combine| keyword.
828A number of standalone functionals are also included within \dalton.
829In addition a number of double-hybrid functionals (energies only) are available,
830which include a post-SCF second-order perturbation theory contribution.
831
832It should be noted that the input is not case sensitive, although the notation
833employed in this manual makes use of case to emphasize exchange or correlation
834functional properties and reflect the original literature sources.
835
836
837\subsubsection{Exchange Functionals}
838\providecommand\exfn[1]{#1}
839\begin{description}
840
841\item[Slater] Dirac-Slater exchange functional
842\cite{dft:hohenberg,dft:kohn,dft:slater}.\index{Slater}
843
844\item[Becke] 1988 Becke exchange GGA correction \cite{dft:becke88}.
845  Note that the full Becke88 exchange functional is given as
846  \exfn{Slater} + \exfn{Becke}.\index{Becke}
847
848\item[mBecke] 1998 modified \exfn{Becke} exchange correction presented in reference
849  \cite{dft:edf1} for use in the EDF1 functional. The $\beta$ value
850  of 0.0042 in \exfn{Becke} is changed to 0.0035.\index{mBecke}\index{EDF1}
851
852\item[B86] Becke 1986 exchange functional, a divergence free, semi-empirical
853    gradient-corrected exchange functional~\cite{dft:b86,dft:b86r}.\index{B86} This
854    functional corresponds to the B86R functional of the Molpro program.
855
856\item[B86mx] B86 exchange functional modified with a gradient correction
857  for large density gradients~\cite{dft:b86mgc}.\index{B86mx}
858
859\item[DBx] Double-Becke exchange functional defined in 1998 by
860  Gill et al.\cite{dft:edf1,dft:edf2} for use in the EDF1 functional.
861  The full DBx functional is defined as
862
863  1.030952*\exfn{Slater} - 8.44793*\exfn{Becke} + 10.4017*\exfn{mBecke}
864  \index{EDF1}\index{Double-Becke}\index{Becke}
865
866\item[DK87x] DePristo and Kress' 1987 rational function GGA exchange functional
867  (equation 7) from Ref. \cite{dft:dk87}.\index{DK87} The full exchange
868  functional is defined as \exfn{Slater} + \exfn{DK87x}.
869
870%\item[FT97ax] Filatov and Thiel 1997 (FT97) exchange functional GGA correction,
871%  variant A.~\cite{dft:ft97}.\index{FT97}
872%  The complete exchange functional is given by \exfn{Slater} + \exfn{FT97ax}.
873%
874%\item[FT97bx] Filatov and Thiel 1997 (FT97) exchange functional GGA correction,
875%  variant B.~\cite{dft:ft97}.\index{FT97} In this variant, the $\beta$ parameter
876%  is a switching function dependent on the density gradient, $\nabla n_{\sigma}$
877%  and only significantly varies from variant A calculated molecular properties
878%  if core electron effects are significant. This is the default exchange functional
879%  in the combined FT97 exchange-correlation functional.
880%  The complete exchange functional is given by \exfn{Slater} + \exfn{FT97bx}.
881
882\item[G96x] Gill's 1996 GGA correction exchange functional~\cite{dft:g96}.\index{G96}
883  The complete exchange functional is given by \exfn{Slater} + \exfn{G96x}.
884
885\item[LG93x] 1993 GGA exchange functional~\cite{dft:lg93,dft:g961lyp}.\index{LG93}
886  The full LG93 exchange functional is given by \exfn{Slater} + \exfn{LG93x}
887
888\item[LRC95x] 1995 GGA exchange functional with correct asymptotic behavior~\cite{dft:lrc95}.\index{LRC95}
889  The LRC95x exchange functional includes the Slater exchange (Eq 6 from original reference).
890
891\item[KTx] Keal and Tozer's 2003 GGA exchange functional. Note that the gradient correction
892  pre-factor constant, $\gamma$, is not included in the KT exchange
893  definition, but rather in the KT1, KT2 and KT3 definitions. The full KT exchange is given by
894  \cite{dft:kt12}\index{KT},
895
896  \exfn{Slater} + $\gamma$\exfn{KTx} ($\gamma$ is -0.006 for KT1,KT2 and -0.004 for KT3).
897
898\item[OPTX] Handy's 2001 exchange functional correction \cite{dft:optx}.\index{OPTX}
899  The full OPTX exchange functional is given by
900  1.05151*\exfn{Slater} - 1.43169*\exfn{OPTX}.
901
902\item[PBEx] Perdew, Burke and Ernzerhof 1996 exchange functional~\cite{dft:pbe}.\index{PBEx}
903
904\item[revPBEx] Zhang and Wang's 1998 revised PBEx exchange functional, with $\kappa$ of 1.245
905  \cite{dft:revpbe}.\index{revPBE}\index{PBE}
906
907\item[RPBEx] Hammer, Hansen and N{\o}rskov's 1999 revised PBEx exchange functional
908  \cite{dft:revpbe}.\index{RPBE}\index{PBE}
909
910\item[mPBEx] Adamo and Barone's 2002 modified PBEx exchange functional~\cite{dft:mpbe}.
911  \index{mPBE}\index{PBE}
912
913\item[PW86x] Perdew and Wang 1986 exchange functional (the PWGGA-I functional)
914  ~\cite{dft:pw86x}.\index{PW86x}
915
916\item[PW91x] Perdew and Wang 1991 exchange functional (the pwGGA-II functional)
917  and includes Slater exchange \cite{dft:pw91}.\index{PW86x} This functional is
918  also given in a separate parameterization in Refs.~\cite{dft:g96,dft:mpw},
919  which is labeled PW91x2, and is defined as
920  \exfn{PW91x} = \exfn{Slater} + \exfn{PW91x2}.
921
922\item[mPW] Adamo and Barone's 1998 modified PW91x GGA correction exchange functional
923  ~\cite{dft:pw91,dft:mpw}. The full exchange functional is given by
924  \exfn{Slater} + \exfn{mPW}.\index{mPW}
925
926\end{description}
927
928\subsubsection{Correlation Functionals}
929\providecommand\corfn[1]{#1}
930\begin{description}
931
932\item[VWN3] correlation functional of Vosko, Wilk and Nusair, 1980 (equation III)
933  \cite{dft:vwn}. This is the form used in the Gaussian program.\index{VWN3}
934
935\item[VWN5] correlation functional of Vosko, Wilk and Nusair, 1980 (equation
936  V -- the recommended one). The VWN keyword is a synonym for VWN5~\cite{dft:vwn}.\index{VWN5}
937
938%\item[FT97c] Filatov and Thiel 1997 (FT97) correlation functional
939%  \cite{dft:ft97}.\index{FT97}
940
941\item[LYP] correlation functional by Lee, Yang and Parr, 1988
942  \cite{dft:lyp1,dft:lyp2}.\index{LYP}
943
944\item[LYPr] 1998 modified \corfn{LYP} functional, which is the re-parameterized EDF1 version
945  with modified parameters (0.055, 0.158, 0.25, 0.3505)
946  \cite{dft:lyp1,dft:lyp2,dft:edf1}.\index{LYPr}\index{EDF1}
947
948\item[P86c] non-local part of the correlation functional of the Perdew 1986 correlation functional
949  \cite{dft:p86}. PZ81 (1981 Perdew local) is usually used for the local part of the
950  functional, with a total corelation functional of \index{P86}\index{PZ81}
951  \corfn{P86c} + \corfn{PZ81}.
952
953\item[PBEc] Perdew, Burke and Ernzerhof 1996 correlation functional,
954  defined as PW91c local and PBEc non-local correlation~\cite{dft:pbe}.\index{PBEc}
955
956\item[PW91c] 1991 correlation functional of Perdew and Wang (the pwGGA-II functional)
957  ~\cite{dft:pw91}.\index{PW91} This functional includes both the PW91c non-local and
958  PW91c local (ie PW92c) contributions. The non-local PW91c contribution may be determined
959  as \corfn{PW91c} - \corfn{PW92c}.
960
961\item[PW92c] local correlation functional of Perdew and Wang, 1992~\cite{dft:pw91,dft:pw92}.\index{PW91}
962  This functional is the local contribution to the PW91c correlation functional.
963
964\item[PW92ac] gradient correction to the PW91c correlation functional of Perdew and Wang,
965  equation 16 from Ref.~\cite{dft:pw91,dft:pw92}.\index{PW91} The PWGGA-IIA functional
966  as defined in the original reference is \corfn{PW91c} + \corfn{PW92ac}.
967
968\item[PZ81] local correlation functional of Perdew and Zunger, 1981~\cite{dft:pz81}.\index{PZ81}
969
970\item[Wigner] original 1938 spin-polarized correlation functional~\cite{dft:wigner}.\index{Wigner}
971
972\item[WL90c] Wilson and Levy's 1990 non-local spin-dependent correlation functional
973  (equation 15 from Ref.~\cite{dft:wl90}).\index{WL90}
974
975\end{description}
976
977\subsubsection{Standalone Functionals}
978\providecommand\onefn[1]{#1}
979\begin{description}
980
981\item[LB94] asymptotically correct functional of Leeuwen and
982  Baerends 1994~\cite{dft:lb94}. This functional improves description of the
983  asymptotic density on the expense of core and inner valence.\index{LB94}
984
985\item[B97] Becke 1997 functional~\cite{dft:b97}.\index{B97}
986
987\item[B97-1] Hamprecht et al.'s 1998 re-parameterization of the
988  B97 functional~\cite{dft:b97-1}.\index{B97}\index{B97-1}
989
990\item[B97-2] Modification of B97 functional in 2001 by Wilson, Bradley and Tozer
991  \cite{dft:b97-2}.\index{B97}\index{B97-2}
992
993\item[B97-D] Grimme's re-parameterization of the B97-1 functional for use with
994empirical dispersion correction~\cite{dft:b97-d}.\index{B97}\index{B97-D}
995
996\item[B97-K] Boese and Martin 2004 re-parameterization of the
997  B97-1 functional for kinetics~\cite{dft:b97-1}.\index{B97}\index{B97-K}
998
999\item[HCTH] is a synonym for the HCTH407 functional (detailed below).
1000  \cite{dft:hcth407}.\index{HCTH}\index{HCTH407}
1001
1002\item[1-4] The ``quarter'' functional of Menconi, Wilson and Tozer
1003  \cite{dft:14}.\index{1-4}\index{1-4}
1004
1005\item[HCTH93] Original 1998 HCTH functional, parameterized on a set of
1006  93 training systems~\cite{dft:hcth93}.\index{HCTH}\index{HCTH93}
1007
1008\item[HCTH120] The HCTH functional parameterized on a set of 120 training systems
1009  in 2000~\cite{dft:hcth120}.\index{HCTH}\index{HCTH120}
1010
1011\item[HCTH147] The HCTH functional parameterized on a set of 147 training systems
1012  in 2000~\cite{dft:hcth120}.\index{HCTH}\index{HCTH147}
1013
1014\item[HCTH407] The HCTH functional parameterized on a set of 407 training systems
1015  in 2001~\cite{dft:hcth407}.\index{HCTH}\index{HCTH407}
1016
1017\item[HCTH407p] The HCTH407 functional re-parameterized in 2003 on a set of 407
1018  training systems and ammonia dimer to incorporate hydrogen bonding
1019  \cite{dft:hcth407p}.\index{HCTH}\index{HCTH407}\index{HCTH407p}
1020
1021\end{description}
1022
1023\subsubsection{Combined functionals}
1024\providecommand\funexample[1]{\\{\tt #1 }}
1025\begin{description}
1026
1027\item[Combine] is a universal keyword allowing users to manually
1028  construct arbitrary linear combinations of exchange and correlation
1029  functionals from the list above. Even\index{Combine} fractional
1030  Hartree--Fock exchange can be specified. This keyword is to be
1031  followed by a string of functionals with associated weights.
1032  The syntax is \verb|NAME=WEIGHT ...|.
1033  As an example, B3LYP may be constructed as:
1034\begin{verbatim}
1035.DFT
1036 Combine HF=0.2 Slater=0.8 Becke=0.72 LYP=0.81 VWN=0.19
1037\end{verbatim}
1038
1039The following GGA and hybrid functional aliases are defined within
1040\dalton\ and provide further examples of the Combine keyword.
1041
1042\item[SVWN5] is a sum of Slater functional and VWN (or VWN5) correlation
1043  functional. SVWN is a synonym for SVWN5. It is equivalent to
1044  \funexample{Combine Slater=1 VWN5=1}
1045  \index{SVWN}
1046
1047\item[SVWN3] is a sum of the Slater exchange functional and VWN3 correlation
1048  functional. It is equivalent to the Gaussian program LSDA functional
1049  and can alternatively be selected by following set of keywords
1050  \funexample{Combine Slater=1 VWN3=1}
1051  \index{SVWN3}
1052
1053\item[LDA] A synonym for SVWN5 (or SVWN). \index{LDA}
1054
1055\item[BVWN] is a sum of the \exfn{Slater} functional, \exfn{Becke} correction and
1056  \corfn{VWN} correlation functional.  It is equivalent to
1057  \funexample{Combine Slater=1 Becke=1 VWN=1}
1058  \index{BVWN}
1059
1060\item[BLYP] is a sum of Slater functional, Becke88 correction and LYP
1061  correlation functional.  It is equivalent to
1062  \funexample{Combine Slater=1 Becke=1 LYP=1}
1063  \index{BLYP}
1064
1065\item[B3LYP] 3-parameter hybrid functional \cite{dft:b3lyp} equivalent to:
1066  \funexample{Combine HF=0.2 Slater=0.8 Becke=0.72 LYP=0.81 VWN=0.19}
1067  \index{B3LYP}
1068
1069\item[B3LYPg] hybrid functional with VWN3 form used for
1070  correlation---this is the form used by the Gaussian quantum chemistry
1071  program. Keyword B3LYPGauss is a synonym for B3LYPg.\index{B3LYPG}
1072  This functional can be explicitely set up by
1073  \funexample{Combine HF=0.2 Slater=0.8 Becke=0.72 LYP=0.81 VWN3=0.19}
1074  \index{B3LYP, Gaussian version}
1075
1076\item[B1LYP] 1-parameter hybrid functional with 25\% exact exchange \cite{dft:b1lyp}.
1077  Equivalent to: \funexample{Combine HF=0.25 Slater=0.75 Becke=0.75 LYP=1}
1078  \index{B3LYP}
1079
1080\item[BP86] Becke88 exchange functional and Perdew86 correlation
1081  functional (with Perdew81 local correlation). The explicit form is:
1082  \funexample{Combine Slater=1 Becke=1 PZ81=1 P86c=1}
1083  \index{BP86}
1084
1085\item[B3P86] variant of \verb|B3LYP| with VWN used for local
1086  correlation  and P86 for the nonlocal part.
1087  \funexample{Combine HF=0.2 Slater=0.8 Becke=0.72 P86c=0.81 VWN=1}
1088  \index{B3P86}
1089
1090\item[B3P86g] variant of \verb|B3LYP| with VWN3 used for local
1091  correlation and P86 for the nonlocal part.
1092  This is the form used by the Gaussian quantum chemistry program.
1093  \funexample{Combine HF=0.2 Slater=0.8 Becke=0.72 P86c=0.81 VWN3=1}
1094  \index{B3P86}\index{B3P86, Gaussian version}
1095
1096\item[BPW91] Becke88 exchange functional and PW91 correlation
1097  functional. The explicit form is:
1098  \funexample{Combine Slater=1 Becke=1 PW91c=1}
1099  \index{BPW91}
1100
1101\item[B3PW91] 3-parameter Becke-PW91 functional, with PW91 correlation
1102  functional. Note that PW91c includes PW92c local correlation, thus only
1103  excess PW92c local correlation is required (coefficient of 0.19).
1104  \funexample{Combine HF=0.2 Slater=0.8 Becke=0.72 PW91c=0.81 PW92c=0.19}
1105  \index{B3PW91}
1106
1107\item[B1PW91] 1-parameter hybrid functional \cite{dft:b1lyp} equivalent to:
1108  \funexample{Combine HF=0.25 Slater=0.75 Becke=0.75 PW91c=1}
1109  \index{B1PW91}
1110
1111\item[B86VWN] is a sum of \exfn{Slater} and \exfn{B86x} exchange functionals and
1112  the \corfn{VWN} correlation functional. It is equivalent to
1113  \funexample{Combine Slater=1 B86x=1 VWN=1}
1114  \index{B86VWN}
1115
1116\item[B86LYP] is a sum of \exfn{Slater} and \exfn{B86x} exchange functionals and
1117  the \corfn{LYP} correlation functional. It is equivalent to
1118  \funexample{Combine Slater=1 B86x=1 LYP=1}
1119  \index{B86LYP}
1120
1121\item[B86P86] is a sum of \exfn{Slater} and \exfn{B86x} exchange functionals and
1122  the \corfn{P86c} correlation functional. It is equivalent to
1123  \funexample{Combine Slater=1 B86x=1 P86c=1}
1124  \index{B86P86}
1125
1126\item[B86PW91] is a sum of \exfn{Slater} and \exfn{B86x} exchange functionals and
1127  the \corfn{PW91c} correlation functional.  It is equivalent to
1128  \funexample{Combine Slater=1 B86x=1 PW91c=1}
1129  \index{B86PW91}
1130
1131\item[BHandH] is an simple Half-and-half functional.
1132  \funexample{Combine HF=0.5 Slater=0.5 LYP=1}
1133  \index{BHandH}
1134
1135\item[BHandHLYP] is another simple Half-and-half functional.
1136  \funexample{Combine HF=0.5 Slater=0.5 Becke=0.5 LYP=1}
1137  \index{BHandH}
1138
1139\item[BW] is the sum of the Becke exchange and Wigner correlation
1140  functionals \cite{dft:wigner,dft:bw}.\index{BW}
1141  \funexample{Combine Slater=1 Becke=1 Wigner=1}
1142
1143\item[CAMB3LYP] Coulomb Attenuated Method Functional of Yanai, Tew and
1144Handy \cite{dft:camb3lyp}. This functional accepts additional arguments
1145\verb|alpha|, \verb|beta| and \verb|mu| to modify the fraction of HF
1146exchange for short-range interactions, additional fraction of HF
1147exchange for long-range interaction and the interaction switching
1148factor $\mu$. This input can be specified as follows:
1149\begin{verbatim}
1150.DFT
1151 CAMB3LYP alpha=0.190 beta=0.460 mu=0.330
1152\end{verbatim}
1153\index{CAMB3LYP}
1154
1155
1156\item[rCAMB3LYP] Revised version of the CAMB3LYP Functional \cite{dft:rcamb3lyp}
1157designed to give near piecewise linear behaviour of the energy vs. particle number.
1158This functional accepts additional arguments \verb|alpha|, \verb|beta| and \verb|mu|
1159with the same meanings and syntax as for the CAMB3LYP functional.\index{rCAMB3LYP}
1160
1161\item[DBLYP] is a sum of the Double-Becke exchange functional and
1162  the LYP correlation functional
1163  \cite{dft:becke88,dft:edf1,dft:lyp1,dft:lyp2}.\index{Double-Becke}
1164 \funexample{Combine Slater=1.030952 Becke=-8.44793 mBecke=10.4017 LYP=1}
1165
1166\item[DBP86] is the sum of the Double-Becke exchange functional and
1167  the P86 correlation functional \cite{dft:becke88,dft:edf1,dft:p86}.\index{Double-Becke}
1168 \funexample{Combine Slater=1.030952 Becke=-8.44793 mBecke=10.4017 P86c=1 PZ81=1}
1169
1170\item[DBPW91] is a sum of the Double-Becke exchange functional and
1171  the PW91 correlation functional \cite{dft:becke88,dft:edf1,dft:pw91}.\index{Double-Becke}
1172 \funexample{Combine Slater=1.030952 Becke=-8.44793 mBecke=10.4017 PW91c=1}
1173
1174\item[EDF1] is a fitted functional of Adamson, Gill and Pople \cite{dft:edf1}.
1175  It is a linear combination of the Double-Becke exchange functional and the revised LYP
1176  functional LYPr.\index{EDF1}
1177 \funexample{Combine Slater=1.030952 Becke=-8.44793 mBecke=10.4017 LYPr=1}
1178
1179\item[EDF2] is a linear combination of the Hartree--Fock exchange and the Double-Becke
1180  exchange, Slater exchange, LYP correlation, revised LYPr correlation and VWN
1181  correlation functionals \cite{dft:edf2}\index{EDF2}.
1182 \funexample{Combine HF=0.1695 Slater=0.2811 Becke=0.6227 mBecke=-0.0551 VWN=0.3029 LYP=0.5998 LYPr=-0.0053}
1183
1184\item[G96VWN] is the sum of the G96 exchange functional and the VWN
1185  correlation functional \cite{dft:g96}.
1186 \funexample{Combine Slater=1 G96x=1 VWN=1}
1187
1188\item[G96LYP] is the sum of the G96 exchange functional and the LYP
1189  correlation functional \cite{dft:g96}.
1190 \funexample{Combine Slater=1 G96x=1 LYP=1}
1191
1192\item[G96P86] is the sum of the G96 exchange functional and the P86
1193  correlation functional \cite{dft:g96}.
1194 \funexample{Combine Slater=1 G96x=1 P86c=1}
1195
1196\item[G96PW91] is the sum of the G96 exchange functional and the PW91
1197  correlation functional \cite{dft:g96}.
1198 \funexample{Combine Slater=1 G96x=1 PW91c=1}
1199
1200\item[G961LYP] is a 1-parameter B1LYP type functional with the exchange gradient
1201  correction provided by the G96x functional \cite{dft:g961lyp}.
1202 \funexample{Combine HF=0.25 Slater=0.75 G96x=0.75 LYP=1}
1203
1204\item[KMLYP] Kang and Musgrave 2-parameter hybrid functional with a mixture of
1205  Slater and Hartree--Fock exchange and VWN and LYP correlation functionals.
1206  \cite{dft:kmlyp}.
1207 \funexample{Combine HF=0.557 Slater=0.443 VWN=0.552 LYP=0.448}
1208
1209\item[KT1] Slater-VWN5 functional with the KT GGA exchange correction
1210  \cite{dft:kt12,dft:kt12a}.\index{KT1}
1211 \funexample{Combine Slater=1 VWN=1 KT=-0.006}
1212
1213\item[KT2] differs from KT1 only in that the weights of the Slater and
1214  VWN5 functionals are from an empirical fit (not equal to 1.0)
1215  \cite{dft:kt12,dft:kt12a}.\index{KT2}
1216  \funexample{Combine Slater=1.07173 VWN=0.576727 KT=-0.006}
1217
1218\item[KT3] a hybrid functional of Slater, OPTX and KT exchange with the
1219  LYP correlation functional \cite{dft:kt3}. The explicit form is
1220  \funexample{Combine Slater=1.092 KT=-0.004 LYP=0.864409 OPTX=-0.925452}
1221  \index{KT3}
1222
1223\item[LG1LYP] is a 1-parameter B1LYP type functional with the exchange gradient
1224  correction provided by the LG93x functional \cite{dft:g961lyp}.
1225 \funexample{Combine HF=0.25 Slater=0.75 LG93x=0.75 LYP=1}
1226
1227\item[mPWVWN] is the combination of mPW exchange and VWN correlation functionals
1228   \cite{dft:mpw,dft:vwn}.\index{mPWVWN}
1229  \funexample{Combine Slater=1 mPW=1 VWN=1}.
1230
1231\item[mPWLYP] is the combination of mPW exchange and LYP correlation functionals
1232   \cite{dft:mpw,dft:vwn}.\index{mPWLYP}
1233  \funexample{Combine Slater=1 mPW=1 LYP=1}.
1234
1235\item[mPWP86] is the combination of mPW exchange and P86 correlation functionals
1236   \cite{dft:mpw,dft:vwn}.\index{mPWP86}
1237  \funexample{Combine Slater=1 mPW=1 P86c=1 PZ81=1}.
1238
1239\item[mPWPW91] is the combination of mPW exchange and PW91 correlation functionals
1240   \cite{dft:mpw,dft:pw91}.\index{mPWPW91}
1241  \funexample{Combine Slater=1 mPW=1 PW91c=1}.
1242
1243\item[mPW3PW91] is a 3-parameter combination of mPW exchange and PW91 correlation
1244  functionals, with the PW91 (PW92c) local correlation~\cite{dft:mpw}.\index{mPW3PW91}
1245  \funexample{Combine HF=0.2 Slater=0.8 mPW=0.72 PW91c=0.81 PW92c=0.19}.
1246
1247\item[mPW1PW91] is a 1-parameter combination mPW exchange and PW91 correlation
1248  functionals with 25\% Hartree--Fock exchange \cite{dft:mpw}.\index{mPW1PW91}
1249  \funexample{Combine HF=0.25 Slater=0.75 mPW=0.75 PW91c=1}.
1250
1251\item[mPW1K] optimizes mPW1PW91 for kinetics of H abstractions, with 42.8\% Hartree--Fock
1252  exchange \cite{dft:mpw1k}.\index{mPW1PW91}
1253  \funexample{Combine HF=0.428 Slater=0.572 mPW=0.572 PW91c=1}.
1254
1255\item[mPW1N] optimizes mPW1PW91 for kinetics of H abstractions, with 40.6\% Hartree--Fock
1256  exchange \cite{dft:mpw1n}.\index{mPW1N}
1257  \funexample{Combine HF=0.406 Slater=0.594 mPW=0.594 PW91c=1}.
1258
1259\item[mPW1S] optimizes mPW1PW91 for kinetics of H abstractions, with 6\% Hartree--Fock
1260  exchange \cite{dft:mpw1s}.\index{mPW1S}
1261  \funexample{Combine HF=0.06 Slater=0.94 mPW=0.94 PW91c=1}.
1262
1263\item[OLYP] is the sum of the OPTX exchange functional with the
1264  LYP correlation functional \cite{dft:optx,dft:lyp1,dft:lyp2}.
1265  \funexample{Combine Slater=1.05151 OPTX=-1.43169 LYP=1}
1266  \index{OLYP}
1267
1268\item[OP86] is the sum of the OPTX exchange functional with the
1269  P86 correlation functional \cite{dft:optx,dft:p86}.
1270  \funexample{Combine Slater=1.05151 OPTX=-1.43169 P86c=1 PZ81=1}
1271  \index{OP86}
1272
1273\item[OPW91] is the sum of the OPTX exchange functional with the
1274  PW91 correlation functional \cite{dft:optx,dft:pw91}.
1275  \funexample{Combine Slater=1.05151 OPTX=-1.43169 PW91c=1}
1276  \index{OPW91}
1277
1278\item[PBE0] a hybrid functional of Perdew, Burke and Ernzerhof with
1279  0.25 weight of exact exchange, 0.75 of \verb|PBEx| exchange functional and
1280  the \verb|PBEc| correlation functional \cite{dft:pbe0}.
1281  Alternative aliases are PBE1PBE or PBE0PBE.\index{PBE0}
1282  \funexample{Combine HF=0.25 PBEx=0.75 PBEc=1}
1283
1284\item[PBE] same as above but with exchange estimated exclusively by
1285  \exfn{PBEx} functional \cite{dft:pbe}.\index{PBE} Alias: PBEPBE.
1286  \funexample{Combine PBEx=1 PBEc=1}
1287
1288\item[RPBE] is a revised PBE functional that employs the
1289  \exfn{RPBEx} exchange functional.
1290  \funexample{Combine RPBEx=1 PBEc=1}
1291
1292\item[revPBE] is a revised PBE functional that employs the
1293  \exfn{revPBEx} exchange functional.
1294  \funexample{Combine revPBEx=1 PBEc=1}
1295
1296\item[mPBE] is a revised PBE functional that employs the
1297  \exfn{mPBEx} exchange functional.
1298  \funexample{Combine mPBEx=1 PBEc=1}
1299
1300\item[PW91VWN] is the combination of PW91 exchange and VWN correlation functionals
1301   \cite{dft:pw91,dft:vwn}.\index{PW91}
1302  \funexample{Combine PW91x=1 VWN=1}.
1303
1304\item[PW91LYP] is the combination of PW91 exchange and LYP correlation functionals
1305   \cite{dft:pw91,dft:lyp1,dft:lyp2}.\index{PW91}
1306  \funexample{Combine PW91x=1 LYP=1}.
1307
1308\item[PW91P86] is the combination of PW91 exchange and P86 (with Perdew 1981 local)
1309  correlation functionals \cite{dft:pw91,dft:pw86,dft:pz81}.
1310  \funexample{Combine PW91x=1 P86c=1 PZ81=1}.
1311
1312\item[PW91PW91] is the combination of PW91 exchange and PW91 correlation functionals.
1313  Equivalent to PW91 keyword \cite{dft:pw91}.
1314  \funexample{Combine PW91x=1 PW91c=1}.
1315
1316\item[XLYP] is a linear combination of \exfn{Slater}, \exfn{Becke} and \exfn{PW91x}
1317  exchange and \corfn{LYP} correlation functionals \cite{dft:xlyp,dft:x3lyp}.\index{XLYP}
1318  \funexample{Combine Slater=1 Becke=0.722 PW91x=0.347 LYP=1}.
1319
1320\item[X3LYP] is a linear combination of Hartree--Fock, \exfn{Slater}, \exfn{Becke}
1321  and \exfn{PW91x} exchange and \corfn{VWN} and \corfn{LYP} correlation functionals
1322  \cite{dft:xlyp,dft:x3lyp}.\index{X3LYP}
1323  \funexample{Combine HF=0.218 Slater=0.782 Becke=0.542 PW91x=0.167 VWN=0.129 LYP=0.871}
1324
1325\end{description}
1326
1327
1328Note that combinations of local and non-local correlation functionals
1329can also be generated with the Combine keyword. For example,
1330\verb|Combine P86c=1 PZ81=1| combines the PZ81 local and P86c non-local
1331correlation functional, whereas \verb|Combine VWN=1 P86c=1|
1332combines the VWN local and P86 non-local correlation functionals.
1333
1334
1335Linear combinations of all exchange and correlation functionals listed above
1336are possible with the \verb|Combine| keyword.
1337
1338\subsubsection{Double-hybrid functionals}
1339\begin{description}
1340\item[B2PLYP] is the double hybrid of Ref.~\cite{dft:b2plyp}
1341
1342\item[B2TPLYP] is a modification of the B2PLYP functional for thermodynamics~\cite{dft:b2tplyp}
1343
1344\item[mPW2PLYP] a double hybrid using an alternative GGA exchange contribution and tested on the G3/05 benchmark dataset~\cite{dft:mpw2plyp}
1345
1346\item[B2GPLYP] is a modification of the B2PLYP functional for general purpose calculations~\cite{dft:b2tplyp}
1347
1348\item[B2PIPLYP] is a form related to B2PLYP but designed to give better performance for sterically crowed or stacked aromatic ring systems~\cite{dft:b2piplyp}
1349
1350\item[PBE0DH] a theoretically derived double-hybrid parameterization~\cite{dft:pbe0dh}
1351
1352\end{description}
1353
1354Note that at present double-hybrid functionals are implemented for energies only, analytic gradient contributions are not implemented.
1355\pagebreak[3]
1356
1357\subsection{\label{ref-srdft}Short-range srDFT functionals}
1358
1359In this sections available srDFT functionals are listed.
1360Note that these functionals may only be specified if one of the
1361srDFT wave functions have been selected.
1362The functonals are actived by specifying them in the input line following the \quotekw{.SRFUN} keyword.
1363The most common srDFT functionals can be specified as a single word, whereas custom combinations of exchange and correlation are specified with two words.
1364The exchange functional must be specified first and the correlation functional second.
1365For example, \verb| SRXPBEGWS SRCPBEGWS| (which is the same combined functional as obtained with the \verb| SRPBEGWS| keyword).
1366
1367\subsubsection{Combined functionals}
1368\providecommand\onefn[1]{#1}
1369\begin{description}
1370
1371\item[SRLDA] combination of \quotekw{SRXLDA} for exchange and \quotekw{SRCVWN5} for correlation~\cite{srdft:LDAERF}
1372
1373\item[LRCLDA] combination of \quotekw{SRXLDA} for exchange and \quotekw{CVWN5} for correlation~\cite{srdft:LDAERF}
1374
1375\item[SRPBEGWS] combination of \quotekw{SRXPBEGWS} for exchange and \quotekw{SRCPBEGWS} for correlation~\cite{srdft:PBEGWSa,srdft:PBEGWSb}
1376
1377\item[LRCPBEGWS] combination of \quotekw{SRXPBEGWS} for exchange and \quotekw{CPBE} for correlation~\cite{srdft:PBEGWSa,srdft:PBEGWSb}
1378
1379\item[SRPBE0GWS] combination of \quotekw{SRXPBEGWS} with \quotekw{.HFXFAC} set to 0.25 for exchange and \quotekw{SRCPBEGWS} for correlation~\cite{srdft:PBEGWSa,srdft:PBEGWSb}
1380
1381\item[SRPBERI] combination of \quotekw{SRXPBEHSE} for exchange and \quotekw{SRCPBERI} for correlation~\cite{srdft:erfgau,srdft:Heyd2004}
1382
1383\end{description}
1384
1385\subsubsection{Exchange Functionals}
1386\providecommand\exfn[1]{#1}
1387\begin{description}
1388
1389\item[NULL] no exchange functional.
1390
1391\item[HFEXCH] 100\% full-range Hartree-Fock like exchange. Combination of HF-like exchange together with an srDFT exchange functional can be obtained with the keyword \quotekw{.HFXFAC}.
1392
1393\item[SRXLDA] a short-range LDA exchange functional based on the uniform electron gas by Paziani \textit{et al.}~\cite{srdft:LDAERF}
1394
1395\item[SRXPBEGWS] short-range GGA exchange functional based on the PBE exchange functional by Goll, Werner and Stoll~\cite{srdft:PBEGWSa,srdft:PBEGWSb}
1396
1397\item[SRXPBEHSE] short-range GGA exchange functional based on the PBE exchange functional by Heyd and Scuseria~\cite{srdft:Heyd2004}
1398
1399\end{description}
1400
1401\subsubsection{Correlation Functionals}
1402\providecommand\corfn[1]{#1}
1403\begin{description}
1404
1405\item[NULL] no correlation functional.
1406
1407\item[SRCVWN5] short-range LDA correlation functional based on VWN5 by Paziani \textit{et al.}~\cite{srdft:LDAERF}
1408
1409\item[CVWN5] full-range LDA correlation functional by Vosko, Wilk and Nusair\cite{dft:vwn}
1410
1411\item[SRCPW92] short-range LDA correlation functional based on PW92 by Paziani \textit{et al.}~\cite{srdft:LDAERF}
1412
1413\item[CPW92] full-range LDA correlation functional by Perdew and Wang, 1992~\cite{dft:pw91,dft:pw92}
1414
1415\item[SRCPBEGWS] short-range GGA correlation functional based on the PBE correlation functional by Goll, Werner and Stoll~\cite{srdft:PBEGWSa,srdft:PBEGWSb}
1416
1417\item[SRCPBERI] short-range GGA correlation functional based on rational interpolation of the PBE correlation functionalbetween the short-range limit and the long-range limit by Toulouse, Colonna and Savin~\cite{srdft:erfgau}
1418
1419\item[CPBE] full-range GGA correlation functional by Perdew, Burke and Ernzerhof~\cite{dft:pbe}
1420
1421\end{description}
1422
1423\subsubsection{Third Options}
1424\providecommand\corfn[1]{#1}
1425\begin{description}
1426
1427\item[NO\_SPINDENSITY] can be put as a third option in the functional specification to force the program to not use spin-densities. This option only works with explicitly specified exchange and correlation functional. For example, \verb|SRXPBEGWS SRCPBEGWS NO_SPINDENSITY|
1428
1429\end{description}
1430\pagebreak[3]
1431
1432\subsection{\label{ref-haminp}\Sec{HAMILTONIAN}}
1433
1434{\bf Purpose:}
1435
1436Add extra terms to the Hamiltonian (for finite field\index{finite field} calculations).
1437
1438\begin{description}
1439\item[\Key{FIELD TERM}]
1440  Default = no finite external fields added. \\
1441  \kw{READ (LUINP,  *  ) EFIELD(NFIELD)} \\
1442  \kw{READ (LUINP,'(A)') LFIELD(NFIELD)} \\
1443  Enter field strength (in atomic units) and property label on separate lines
1444  where label is a \molecule-style property label on the file \verb|AOPROPER|
1445  produced by the property module, see Chapter~\ref{ch:hermit}.
1446  The calculation of the necessary property integral(s) must be requested
1447  in the \quotekw{**INTEGRALS} input module. \\
1448  NOTE: Only real (symmetric) operators are allowed, becaus the wave-function
1449  choices are only implemented for real wave functions. \\
1450  NOTE: This keyword may be repeated several times for adding more than
1451  one finite field (max \mxfelt fields). Example, to specify $\oper{H}' = 0.1 \oper{x} + 0.2 \oper{y}$:
1452
1453\begin{inputex} \begin{verbatim}
1454.FIELD TERM
1455 0.1
1456 XDIPLEN
1457.FIELD TERM
1458 0.2
1459 YDIPLEN
1460\end{verbatim} \end{inputex}
1461
1462\item[\Key{PRINT}]
1463  Default = 0.\\
1464  \kw{READ (LUINP,*) IPRH1} \\
1465  If greater than zero:
1466  print the one-electron Hamiltonian matrix, including
1467  specified field-dependent terms, in AO basis.
1468\end{description}
1469
1470\pagebreak[3]
1471\subsection{\label{ref-mp2inp}\Sec{MP2 INPUT}}
1472
1473{\bf Purpose:}
1474
1475\index{MP2}\index{M{\o}ller-Plesset!second-order}
1476To direct MP2 calculation. Note that MP2 energies as well as
1477properties also are available through the coupled cluster module, see
1478Chapter~\ref{ch:CC}.
1479For open--shell SCF, the singly occupied orbitals are frozen in the MP2 section.
1480
1481\begin{description}
1482
1483\item[\Key{MP2 FROZEN}]
1484  Default = no frozen orbitals\\
1485  \kw{READ (LUINP,*) (NFRMP2(I),I=1,NSYM)} \\
1486  Occupied SCF orbitals frozen in MP2 calculation.
1487
1488\item[\Key{PRINT}] \ \\
1489  \kw{READ (LUINP,*) IPRMP2} \\
1490  Print level for MP2 calculation
1491  (default is the general print level from \verb|**DALTON| plus four).
1492
1493\item[\Key{SAVE WF1}] \ \\
1494  Save first order wave function on SIRIFC.
1495  Default is only to save first order wave function if MP2 is the last wave function level
1496  \emph{and} at least one of the modules PROPERTIES (ABACUS) or RESPONSE have been
1497  requested (presumably then for a SOPPA calculation).
1498
1499\end{description}
1500
1501\subsubsection*{Modifications of MP2 model.}
1502
1503\begin{description}
1504
1505\item[\Key{SCSMP2}]
1506  Grimme's spin-component scaled MP2 ($p_S = 1.2$, $p_T = 1/3$)
1507
1508\item[\Key{SOSMP2}]
1509  Head-Gordon's scaled opposite spin MP2 ($p_S = 1.3$, $p_T = 0$)
1510
1511\item[\Key{MP2 SCALED}] \ \\
1512  \kw{READ (LUINP,*) p\_S, p\_T} \\
1513  Your own scaling factors for a scaled MP2 model.
1514
1515\item[\Key{LEVELSHIFT}] \ \\
1516  \kw{READ (LUINP,*) MP2\_LSHIFT} \\
1517  Level shift of MP2 denominators.
1518\end{description}
1519
1520\noindent{\bf Comments:}
1521
1522The MP2 module expects canonical Hartree--Fock orbitals. The MP2 module will
1523check the orbitals and it exits if the Fock matrix has off-diagonal non-negligible
1524elements.
1525If starting from saved canonical Hartree--Fock orbitals from a previous calculations,
1526although no Hartree--Fock calculation will be done
1527the number of occupied Hartree--Fock orbitals in each symmetry must anyway be
1528specified with the \quotekw{.DOUBLY OCCUPIED} under \quotekw{*SCF INPUT}.
1529
1530The MP2 calculation will produce the MP2 energy and the natural orbitals
1531{natural orbitals!MP2}
1532for the density matrix through second order.  The primary purpose of
1533this option is to generate good starting orbitals for CI or MCSCF wave
1534functions, but it
1535may of course also be used to obtain the MP2 energy, perhaps with frozen
1536core orbitals. {\em For valence MCSCF calculations it is recommended that the
1537\quotekw{\Key{MP2 FROZEN}} option is used in order to obtain the appropriate
1538correlating orbitals\index{correlating orbitals}\index{MCSCF} as start
1539for an MCSCF calculation.\/}  As the commonly
1540used basis sets do not contain correlating orbitals for the core
1541orbitals and as the core correlation energy therefore becomes arbitrary,
1542the \quotekw{\Key{MP2 FROZEN}} option can also be of benefit in MP2 energy
1543calculations.
1544
1545\pagebreak[3]
1546\subsection{\label{ref-nevpt2inp}\Sec{NEVPT2 INPUT}}
1547
1548{\bf Purpose:}
1549
1550\index{NEVPT2}\index{multireference PT!second-order}
1551Calculation of the second order correction to the energy for a
1552CAS--SCF or CAS--CI zero order wavefunction.
1553The user is referred to Chapter~\ref{ch:nevpt2} on
1554page~\pageref{ch:nevpt2}  for a brief
1555introduction to the $n$--electron valence state second order
1556perturbation theory (NEVPT2).
1557
1558\begin{description}
1559\item[\Key{THRESH}]
1560 Default = 0.0\\
1561  \kw{READ (LUINP,*) THRNEVPT} \\
1562  Threshold to discard small coefficients in the CAS wavefunction
1563
1564\item[\Key{FROZEN}]
1565  Default = no frozen orbitals\\
1566  \kw{READ (LUINP,*) (NFRNEVPT2(I),I=1,NSYM)} \\
1567  Orbitals frozen in NEVPT2 calculation
1568
1569\item[\Key{STATE}]
1570 No default provided\\
1571\kw{READ (LUINP,*) ISTNEVCI} \\
1572Root number in a CASCI calculation. This keyword is unnecessary
1573(ignored) in the CASSCF case.
1574\end{description}
1575
1576
1577\noindent{\bf Comments:}
1578
1579
1580%The present version of the NEVPT2 module requires the
1581%\quotekw{\Key{DETERMINANTS}} option  to be set.
1582
1583The use of canonical orbitals for the core and virtual orbitals is
1584strongly recommended since this choice guarantees compliance of the
1585results with a totally invariant form of NEVPT2 (see page~\pageref{ch:nevpt2}).
1586
1587At present the NEVPT2 module can deal with active spaces of dimension
1588not higher than 14.
1589
1590\pagebreak[3]
1591\subsection{\label{ref-optinp}\Sec{OPTIMIZATION}}
1592
1593{\bf Purpose:}
1594
1595To change defaults for optimization of an MCSCF\index{MCSCF} wave function,
1596to specify which state to converge to (lowest state or higher state in specified symmetry),
1597to invoke use of super symmetry\index{super symmetry},
1598and to specify CORE HOLE calculations.\\
1599Some of the options also affect a QC-HF optimization.
1600
1601\begin{description}
1602\item[\Key{ABSORPTION}] \ \\
1603  \kw{READ (LUINP,'(A8)') RWORD} \\
1604  RWORD = ` LEVEL 1', ` LEVEL 2', or ` LEVEL 3'\\
1605  Orbital absorption\index{orbital absorption} in MCSCF optimization
1606  at level 1, 2, or 3, as specified
1607  (normally level 3, see comments below).  This keyword may be repeated to
1608  specify more than one absorption level, the program will then begin with
1609  the lowest level requested and, when that level is converged,
1610  disable the lower level and shift to the next level.
1611% 940816-hjaaj: The following may not be true for RAS ????
1612% Absorption at several levels are only useful in
1613% first macro iteration, therefore the lower levels are disabled after
1614% convergence.
1615
1616\item[\Key{ACTROT}]
1617  include specified active-active rotations
1618\begin{verbatim}
1619  READ (LUINP,*) NWOPT
1620  DO I = 1,NWOPT
1621    READ (LUINP,*) JWOP(1,I),JWOP(2,I)
1622  END DO
1623\end{verbatim}
1624  JWOP(1:2,I) denotes normal molecular orbital numbers (not the active
1625  orbital numbers).
1626
1627\item[\Key{ALWAYS ABSORPTION}]
1628  Absorption\index{orbital absorption} in all MCSCF macro iterations
1629  (default is to disable absorption in
1630  local region or after \quotekw{\Key{MAXABS}} macro iterations, whichever comes first).
1631  Absorption is always disabled after Newton-Raphson algorithm has been used,
1632  and thus also when doing \quotekw{\Key{CORERELAX}},
1633  because absorption may cause variational collapse if the desired state is excited.
1634
1635\item[\Key{CI PHP MATRIX}]
1636  Default : MAXPHP = 1 (Davidson's algorithm)\\
1637  \kw{READ (LUINP,*) MAXPHP} \\
1638  PHP is a subblock of the CI matrix which is calculated explicitly
1639  in order to obtain improved CI trial vectors compared to the
1640  straight Davidson\index{Davidson algorithm} algorithm.  The
1641  configurations corresponding to
1642  the lowest diagonal elements are selected, unless
1643  \quotekw{\Key{PHPRESIDUAL}} is specified.
1644  \kw{MAXPHP} is the maximum dimension of PHP, the actual dimension
1645  will be less if \kw{MAXPHP} will split degenerate configurations.
1646
1647\item[\Key{COREHOLE}] \ \\
1648  \kw{READ (LUINP,*) JCHSYM,JCHORB} \\
1649  JCHSYM = symmetry of core orbital\\
1650  JCHORB = the orbital in symmetry JCHSYM with a single core hole\\
1651  Single core hole\index{core hole} MCSCF calculation. The calculation must be of RAS type
1652  with only the single core-hole orbital in RAS1, the state specified with
1653  \quotekw{\Key{STATE}} is optimized with the core-hole orbital
1654  frozen\index{frozen core hole}.
1655  The specified core hole orbital must be either inactive or
1656  the one RAS1 orbital, if it is inactive then it will switch places with
1657  the RAS1 orbital and it will not be possible to also
1658  specify \quotekw{\Key{REORDER}}. If explicit reordering is required you must reorder
1659  the core orbital yourself and let \kw{JCHORB} point to the one RAS1 orbital.
1660  Orbital absorption is activated at level 2. See comments below for more information.
1661
1662\item[\Key{CORERELAX}]
1663  (ignored if \quotekw{\Key{COREHOLE}} isn't also specified)\\
1664  Optimize state with relaxed core orbital\index{relaxed core hole} (using Newton-Raphson algorithm,
1665  it is not necessary to explicitly specify \quotekw{\Key{NR ALWAYS}}).
1666  It is assumed that this calculation follows an optimization
1667  with frozen core orbital and that the orbital has already been
1668  moved to the RAS1 space ({\it i.e.\/}, the specific value of
1669  \quotekw{JCHORB} under \quotekw{\Key{COREHOLE}} is ignored). Any
1670  orbital absorption   will be ignored.
1671
1672\item[\Key{DETERMINANTS}]
1673  Use determinant\index{determinants} basis instead of CSF basis (see comments).
1674
1675\item[\Key{EXACTDIAGONAL}]
1676  Default for RAS calculations.\\
1677  Use the exact orbital Hessian\index{orbital Hessian} diagonal.
1678
1679\item[\Key{FOCKDIAGONAL}]
1680  Default for CAS calculations.\\
1681  Use an approximate orbital Hessian diagonal which only uses Fock
1682  contributions.
1683
1684\item[\Key{FOCKONLY}]
1685  Activate TRACI option (default : program decides).\\
1686  Modified TRACI option where all orbitals, also active orbitals, are
1687  transformed to Fock type orbitals in each iteration.
1688
1689\item[\Key{FROZEN CORE ORBITALS}] \ \\
1690  \kw{READ (LUINP,*) (NFRO(I),I=1,NSYM)} \\
1691  Frozen orbitals : Number of inactive (doubly occupied) orbitals to be frozen
1692  in each symmetry (the first NFRO(I) in symmetry I) in MCSCF.\index{frozen orbitals!MCSCF}
1693  Active orbitals and specific inactive orbitals can be frozen with \quotekw{.FREEZE}
1694  under \Sec{ORBITAL INPUT}.
1695  Frozen orbitals in SCF are specified in the \Sec{SCF INPUT} input module.
1696
1697\item[\Key{MAX CI}] \ \\
1698  \kw{READ (LUINP,*) MAXCIT} \\
1699  maximum number of CI iterations before MCSCF (default = 3).
1700
1701\item[\Key{MAX MACRO ITERATIONS}] \ \\
1702  \kw{READ (LUINP,*) MAXMAC} \\
1703  maximum number of macro iterations in MCSCF optimization (default = 25).
1704\index{iteration number!MCSCF macro, max}
1705
1706\item[\Key{MAX MICRO ITERATIONS}] \ \\
1707  \kw{READ (LUINP,*) MAXJT} \\
1708  maximum number of micro iterations per macro iteration in MCSCF optimization
1709  (default = 24).
1710
1711\item[\Key{MAXABS}] \ \\
1712  \kw{READ (LUINP,*) MAXABS} \\
1713  maximum number of macro iterations with
1714  absorption\index{orbital absorption} (default = 3).
1715
1716\item[\Key{MAXAPM}] \ \\
1717  \kw{READ (LUINP,*) MAXAPM} \\
1718  maximum number orbital absorptions\index{orbital absorption} within
1719  a macro iteration
1720  (APM : Absorptions Per Macro iteration; default = 5)
1721
1722\item[\Key{NATONLY}]
1723  Activate TRACI option (default : program decides).\\
1724  Modified TRACI option where the inactive and secondary orbitals are not
1725  touched (these two types of orbitals are already natural orbitals).
1726
1727\item[\Key{NEO ALWAYS}]
1728  Always norm-extended optimization (never switch to New\-ton-Raph\-son).
1729  Note: \quotekw{\Key{NR ALWAYS}} and \quotekw{\Key{CORERELAX}}
1730  takes precedence over \quotekw{\Key{NEO ALWAYS}}.
1731
1732\item[\Key{NO ABSORPTION}]
1733  Never orbital absorption\index{orbital absorption} (default settings removed)
1734
1735\item[\Key{NO ACTIVE-ACTIVE ROTATIONS}]
1736  No active-active rotations in RAS optimization.
1737
1738\item[\Key{NOTRACI}]
1739  Disable TRACI option (default : program decides).
1740
1741\item[\Key{NR ALWAYS}]
1742  Always Newton-Raphson optimization (never NEO optimization).
1743  Note: \quotekw{\Key{NR ALWAYS}} takes precedence over
1744  \quotekw{\Key{NEO ALWAYS}}.
1745
1746\item[\Key{OLSEN}]
1747  Use Jeppe Olsen's generalization of the Davidson
1748  algorithm\index{Davidson algorithm}.
1749
1750\item[\Key{OPTIMAL ORBITAL TRIAL VECTORS}]
1751  Generate "optimal" orbital trial
1752  vectors~\cite{hjajpjhajcp87}.\index{optimal orbital trial vector}
1753
1754\item[\Key{ORB\_TRIAL VECTORS}]
1755  Use also orbital trial vectors as start vectors for auxiliary roots
1756  in each macro iteration (CI trial vectors are always generated).
1757
1758\item[\Key{PHPRESIDUAL}]
1759  Select configurations for PHP matrix based on largest residual
1760  rather than lowest diagonal elements.
1761
1762\item[\Key{SIMULTANEOUS ROOTS}]
1763  Default : NROOTS = ISTATE, LROOTS = NROOTS\\
1764  \kw{READ (LUINP,*) NROOTS, LROOTS} \\
1765  NROOTS = Number of simultaneous roots in NEO\\
1766  LROOTS = Number of simultaneous roots in NEO at start
1767
1768\item[\Key{STATE}]
1769  Default = 1\\
1770  \kw{READ (LUINP,*) ISTATE} \\
1771  Index of MCSCF Hessian\index{MCSCF Hessian} at convergence (1 for
1772  lowest state, 2 for first
1773  excited state, etc. within the spatial symmetry\index{symmetry} and
1774  spin symmetry\index{spin symmetry}
1775  specified under \Sec{CONFIGURATION INPUT}).
1776
1777\item[\Key{SUPSYM}]
1778  Enforce automatic identification of "super symmetry"
1779  \index{super symmetry} (see comments and .THRSSY keyword below).\\
1780  Default is that "super symmetry" is not identified.
1781
1782\item[\Key{SYM CHECK}]
1783  Default: ICHECK = 2 when NROOTS $>$ 1, else ICHECK = -1.\\
1784  \kw{READ (LUINP,*) ICHECK} \\
1785  Check symmetry of the LROOTS start CI-vectors and remove those which
1786  have wrong symmetry ({\it e.g.\/} vectors of delta symmetry in a sigma
1787  symmetry calculation).
1788\begin{verbatim}
1789  ICHECK < 0  : No symmetry check.
1790  ICHECK = 1  : Remove those vectors which do not have the same
1791                symmetry as the ISTATE vector, reassign ISTATE.
1792  ICHECK = 2  : Remove those vectors which do not have the same
1793                symmetry as the lowest state vector before selecting
1794                the ISTATE vector.
1795  other values: check symmetry, do not remove any CI vectors.
1796\end{verbatim}
1797  The \quotekw{\Key{SIMULTANEOUS ROOTS}} input will automatically be
1798  updated if CI vectors are removed.
1799
1800\item[\Key{THRCGR}] \ \\
1801  \kw{READ (LUINP,*) THRCGR} \\
1802  Threshold for print of CI gradient. Default is 0.1D0.
1803
1804\item[\Key{THRESH}]
1805  Default = 1.0D-05\\
1806  \kw{READ (LUINP,*) THRMC} \\
1807  Convergence threshold for energy gradient in MCSCF optimization.
1808  The convergence of the energy will be approximately the square of this
1809  number.
1810
1811\item[\Key{THRSSY}] \ \\
1812  \kw{READ (LUINP,*) THRSSY} \\
1813  Threshold for identification of "super
1814  symmetry"\index{super symmetry} and degeneracies among
1815  "super symmetries" from matrix elements of the kinetic energy matrix
1816  (default: 5.0D-8).
1817
1818\item[\Key{TRACI}]
1819  Activate TRACI option (default : program decides).\\
1820  Active orbitals are transformed to natural orbitals and the CI-vectors
1821  are counter-rotated such that the CI states do not change.  The
1822  inactive and secondary orbitals are transformed to Fock type orbitals
1823  (corresponding to canonical orbitals for closed shell Hartree--Fock).
1824  For RAS wave functions the active orbitals are only transformed
1825  within their own class (RAS1, RAS2, or RAS3) as the wave function is
1826  not invariant to orbital rotations between the classes.  For RAS, the
1827  orbitals are thus not true natural orbitals, the density matrix is
1828  only block diagonalized.  Use \quotekw{\Key{IPRCNO}} (see
1829  p.~\pageref{ref-priinp})   to control output from this
1830  transformation.
1831
1832\end{description}
1833
1834
1835\noindent{\bf Comments:}
1836
1837COREHOLE: Single core-hole\index{core hole} calculations are
1838performed as RAS calculations where the opened core orbital is in
1839the RAS1 space.  The RAS1 space must therefore contain one and
1840only one orbital when the COREHOLE option is used, and the
1841occupation must be restricted to be exactly one electron. The
1842orbital identified as the core orbital must be either inactive or
1843the one RAS1 orbital, if it is inactive it will switch places with
1844the one RAS1 orbital. The core orbital (now in RAS1) will be
1845frozen in the following optimization. After this calculation has
1846converged, the CORERELAX option may be added and the core orbital
1847will be relaxed\index{relaxed core hole}.  When CORERELAX is
1848specified it is assumed that the calculation was preceded by a
1849frozen core\index{frozen core hole} calculation, and that the
1850orbital has already been moved to the RAS1 space. Default
1851corresponds to the main peak, shake-up energies may be obtained by
1852specifying \quotekw{\Key{STATE}} larger than one. Absorption is
1853very beneficial in core hole calculations because of the large
1854orbital relaxation following the opening of the core hole.
1855
1856ABSORPTION: Absorption\index{orbital absorption} level 1 includes occupied - occupied rotations
1857only (including active-active rotations); level 2 adds inactive -
1858secondary rotations and only active - secondary rotations are excluded
1859at this level; and finally level 3 includes all non-redundant rotation
1860for the frozen CI vector.  Levels 1 and 2 require the same integral
1861transformation (because the inactive - secondary rotations are
1862performed using the P-supermatrix integrals) and level 1 is therefore
1863usually not used. Level 3 is the normal and full level, but it can be
1864advantageous to activate level 2 together with level 3 if big
1865inactive-active or occupied-occupied rotations are expected.
1866
1867ORB\_TRIAL: Orbital trial\index{orbital trial vector}\ vectors as
1868start vectors can be used for
1869excited states and other calculations with more than one simultaneous
1870roots.  The orbital start trial vectors are based on the eigenvectors of
1871the NEO matrix in the previous macro iterations.  However, they are
1872probably not cost-effective for multiconfiguration calculations where
1873optimal orbital trial\index{optimal orbital trial vector} vectors are
1874used and they are therefore not used
1875by default.
1876
1877If \quotekw{\Key{SUPSYM}} is specified, then
1878{\sir} automatically identifies "super symmetry"\index{super symmetry!orbitals},
1879{\it i.e.\/} it assigns orbitals to the irreps of the true point
1880group of the molecule\index{symmetry!group} which is a
1881"super group" of the Abelian group used in the calculation.
1882Degenerate orbitals will be averaged and the "super symmetry"
1883will be enforced in the orbitals.
1884Note that "super symmetry" can only be used
1885in the RHF, MP2, MCSCF, and RESPONS modules, and should
1886not be invoked if other modules are used,
1887for example, if \Sec{*PROPERTIES} (\aba) is invoked.
1888%hj aug 04: it should be OK for closed shell cases, also for CC ???
1889% it is only for spatially degenerate states that elements
1890% of the orbital gradient may be non-zero, right ???
1891Also, it cannot be used
1892in finite field calculations where the field lowers the symmetry.
1893The initial orbitals must be symmetry orbitals, and the super symmetry
1894analysis is performed on the kinetic energy matrix in this basis.
1895The \quotekw{.THRSSY} option is used to define when the kinetic
1896energy matrix element between two orbitals is considered to be
1897zero and when two diagonal matrix elements are degenerate. In the
1898first case the orbitals can belong to different irreps of the
1899supergroup and in the second case the two orbitals are considered
1900to be degenerate. The analysis will fail if there are accidental
1901degeneracies in diagonal elements.  This can happen if the nuclear
1902geometry deviates slightly from a higher symmetry point group, for
1903example because too few digits has been used in the input of the
1904nuclear geometry. If the program stops because the super symmetry
1905analysis fails with a degeneracy error, you might consider to use
1906more digits in the nuclear coordinates, to change \kw{THRSSY}, or
1907to disable super symmetry by not using \quotekw{.SUPSYM}.  The value of
1908\kw{THRSSY} should be sufficiently small to avoid accidental
1909degeneracies and sufficiently large to ignore small errors in
1910geometry and numerical round-off errors.
1911
1912
1913SYM CHECK: The symmetry check is performed on the matrix element
1914$\langle VEC1 \mid oper \mid VEC2\rangle$, where "oper" is
1915the CI-diagonal.
1916It is recommended and the default to use \quotekw{\Key{SYM CHECK}}
1917for excited states, including
1918CI vectors of undesired symmetries is a waste of CPU time.
1919
1920DETERMINANTS: The kernels of the CI sigma routines and density matrix
1921routines are always performed in determinant\index{determinants}
1922basis.  However, this
1923keyword specifies that the external representation is Slater
1924determinants as well.  The default is that the external representation
1925is in CSF\index{CSF}\index{configuration state function} basis as
1926described in chapter 8 of MOTECC-90.  The external
1927CSF\index{CSF}\index{configuration state function} basis is
1928generally to be preferred to be sure that the converged
1929state(s) have pure and correct spin symmetry\index{spin symmetry}, and
1930to save disk space.
1931It is recommended to specify \quotekw{\Key{PLUS COMBINATIONS}} under
1932\quotekw{\Sec{CI VECTOR}} for
1933calculations on singlet states\index{singlet state} with
1934determinants\index{determinants},
1935in particular for
1936excited singlet\index{excited state} states which often have lower lying triplet states.
1937
1938
1939\pagebreak[3]
1940\subsection{\label{ref-orbinp}\Sec{ORBITAL INPUT}}
1941
1942{\bf Purpose:}
1943
1944To define an initial set of molecular orbitals\index{molecular orbital!initial set}
1945and to control frozen orbitals\index{frozen orbitals}, deletion of orbitals\index{delete orbitals},
1946reordering and punching of orbitals.
1947
1948\begin{description}
1949\item[\Key{5D7F9G}]
1950  Delete unwanted components in Cartesian d, f, and g orbitals.
1951  (s in d; p in f; s and d in g). By default, \her\ provides atomic
1952  integrals in spherical basis, and this option should therefore not
1953  be needed nowadays.
1954
1955\item[\Key{AO DELETE}] \ \\
1956  \kw{READ (LUINP,*) THROVL } \\
1957  Delete MO's based on canonical orthonormalization using eigenvalues
1958  and eigenvectors of the AO overlap matrix.\index{linear dependence} \\
1959  THROVL: limit for basis
1960  set numerical linear dependence (eigenvectors with eigenvalue less
1961  than THROVL are excluded). Default is 1.0$\cdot$10$^{-6}$.
1962
1963\item[\Key{CMOMAX}] \ \\
1964  \kw{READ (LUINP,*) CMAXMO} \\
1965  Abort calculation if the absolute value of any initial MO coefficient is
1966  greater than CMAXMO (default : CMAXMO = $10^3$).  Large MO coefficients
1967  can cause significant loss of accuracy in the two-electron integral
1968  transformation.
1969
1970\item[\Key{DELETE}] \ \\
1971  \kw{READ (LUINP,*) (NDEL(I),I = 1,NSYM) } \\
1972  Delete orbitals\index{deleted orbitals}, {\it i.e.\/} number of molecular orbitals
1973  in symmetry \quotekw{I} is number of basis functions in symmetry \quotekw{I} minus
1974  \quotekw{NDEL(I)}. \\
1975  Only for use with \quotekw{.MOSTART} options \quotekw{FORM12} or \quotekw{FORM18},
1976  it cannot be used with \quotekw{H1DIAG}, \quotekw{EWMO}, or \quotekw{HUCKEL},
1977  and the other restart options as \quotekw{NEWORB} reads this information from file
1978  and this will overwrite what ever was specified here.
1979
1980\item[\Key{FREEZE}]
1981  Default: no frozen orbitals.
1982\begin{verbatim}
1983  READ (LUINP,*) (NNOR(ISYM), ISYM = 1,NSYM)
1984  DO ISYM = 1,NSYM
1985    IF (NNOR(ISYM) .GT. 0) THEN
1986      READ (LUINP,*) (INOROT(I), I = 1,NNOR(ISYM))
1987      ...
1988    END IF
1989  END DO
1990\end{verbatim}
1991  where \kw{INOROT} = orbital numbers of the orbitals to be
1992          frozen\index{frozen orbitals!MCSCF and SCF} (not rotated)
1993          in symmetry \quotekw{ISYM} both in SCF and MCSCF
1994          after any reordering (counting from 1 in each symmetry).\\
1995  Must be specified after all options reducing the number of orbitals.
1996  Frozen occupied orbitals in SCF can only be specified in the \Sec{SCF INPUT} input module
1997  and frozen inactive orbitals in MCSCF can only be specified in the \Sec{OPTIMIZATION}
1998  input module.
1999
2000\item[\Key{GRAM-SCHMIDT ORTHONORMALIZATION}]
2001  Default.\\
2002  Gram--Schmidt orthonormalization\index{orthonormalization!Gram--Schmidt} of input orbitals.
2003
2004\item[\Key{LOCALIZATION}] \ \\
2005  \kw{READ (LUINP,*) REWORD} \\
2006  Specify that the doubly occupied (inactive) orbitals should be localized after SCF
2007  or MCSCF is converged.
2008  Two options for localization of the orbitals are currently available:
2009  \begin{description}
2010  \item[{\tt BOYLOC\ }] Use the Boys localization scheme~\cite{Boyloc}.
2011  %\item[{\tt PIPLOC\ }] Use the Pipek-Mezey localization scheme~\cite{}.
2012  % aug 04: PIPLOC is not implemented yet.
2013  \item[{\tt SELECT\ }] Select a subset of the orbitals to be localized. The first
2014  line following this option contains the number orbitals to localize per symmetry,
2015  and the following lines contain which orbitals to localize within each symmetry,
2016  one line per symmetry with orbitals to localize.
2017  This option is typically used for localizing degenerate
2018  core orbitals, leaving all other orbitals intact.
2019  \begin{verbatim}
2020         READ(LUCMD,*)(NBOYS(I),I=1,NSYM)
2021         DO I=1,NSYM
2022            IF (NBOYS(I).GT.0) THEN
2023               READ(LUCMD,*)(BOYSORB(J,I),J=1,NBOYS(I))
2024            END IF
2025         END DO
2026   \end{verbatim}
2027  \end{description}
2028
2029\item[\Key{MOSTART}]
2030   Molecular orbital input\index{molecular orbital}\\
2031   \kw{READ (LUINP,'(1X,A6)') RWORD} \\
2032   where RWORD is one of the following:
2033   \begin{description}
2034   \item[{\tt FORM12\ }] Formatted input (6F12.8)  supplied after
2035        \Sec{*MOLORB} or \Sec{*NATORB} keyword. Use also \quotekw{.DELETE}
2036        if orbitals were deleted.
2037   \item[{\tt FORM18\ }] Formatted input (4F18.14) supplied after
2038        \Sec{*MOLORB} or \Sec{*NATORB} keyword. Use also \quotekw{.DELETE}
2039        if orbitals were deleted.
2040   \item[{\tt EWMO\ }] Start orbitals generated by projecting the EWMO
2041        H{\"u}ckel eigenvectors in a good generally contracted ANO basis set
2042        onto the present basis set.
2043        The EWMO model generally works better than the EHT model.
2044        Default initial guess for molecules in which all atoms have a nuclear charge
2045        less than or equal to 36.
2046        Note: EWMO/HUCKEL is not implemented yet if any element has a
2047        charge larger than 36).
2048        The start density will thus be close to one generated from atomic densities,
2049        but with molecular valence interaction in the EWMO model.
2050        This works a lot better than using a minimal basis set for EWMO.
2051   \item[{\tt HUCKEL\ }] Start orbitals generated by projecting the EHT
2052        H{\"u}ckel eigenvectors in a good generally contracted ANO basis set
2053        onto the present basis set.
2054        Note: EWMO/HUCKEL is not implemented yet if any element has a
2055        charge larger than 36.
2056        The start density will thus be close to one generated from atomic densities,
2057        but with molecular valence interaction in the H{\"u}ckel model.
2058        This works a lot better than using a minimal basis set for H{\"u}ckel.
2059   \item[{\tt H1DIAG\ }] Start orbitals that diagonalize
2060        one-electron Hamiltonian matrix (default
2061        for molecules containing elements with a nuclear larger than 36).
2062   \item[{\tt NEWORB\ }] Input from {\sir} restart file
2063                            (\verb|SIRIUS.RST| file) with label \quotekw{NEWORB  }
2064   \item[{\tt OLDORB\ }] Input from {\sir} restart file
2065                            (\verb|SIRIUS.RST| file) with label \quotekw{OLDORB  }
2066   \item[{\tt SIRIFC\ }] Input from {\sir} interface file ("\verb|SIRIFC|")
2067\end{description}
2068
2069\item[\Key{PUNCHINPUTORBITALS}]
2070  Punch input orbitals with label \Sec{*MOLORB}, Format (4F18.14).
2071  These orbitals may {\it e.g.\/} be transferred to another computer and
2072  read there with \quotekw{.MOSTART} followed by \quotekw{ FORM18} on
2073  next line from this input section.
2074
2075\item[\Key{PUNCHOUTPUTORBITALS}]
2076  Punch final orbitals with label \Sec{*MOLORB}, Format (4F18.14).
2077  These orbitals may {\it e.g.\/} be transferred to another computer and
2078  read there with \quotekw{.MOSTART} followed by \quotekw{ FORM18} on
2079  next line from this input section.
2080
2081\item[\Key{REORDER}]
2082Default: no reordering.
2083\begin{verbatim}
2084  READ (LUINP,*) (NREOR(I), I = 1,NSYM)
2085  DO I = 1,NSYM
2086     IF (NREOR(I) .GT. 0) THEN
2087        READ (LUINP,*) (IMONEW(J,I), IMOOLD(J,I), J = 1,NREOR(I))
2088     END IF
2089  END DO
2090  NREOR(I) = number of orbitals to be reordered in symmetry I
2091  IMONEW(J,I), IMOOLD(J,I) are orbital numbers in symmetry I.
2092
2093For example if orbitals 1 and 5 in symmetry 1 should change place, specify
2094.REORDER
2095 2 0 0 0
2096 1 5 5 1
2097\end{verbatim}
2098  Reordering of molecular orbitals (see comments).
2099
2100\item[\Key{SYMMETRIC ORTHONORMALIZATION}]
2101  Default: Gram-Schmidt orthonormalization\\
2102  Symmetric orthonormalization of input
2103  orbitals\index{orthonormalization!symmetric}.
2104
2105\end{description}
2106
2107
2108\noindent{\bf Comments:}
2109
2110\Key{REORDER}\index{orbital reordering} can for instance be used for
2111linear molecules to interchange
2112undesired delta orbitals among the active orbitals in symmetry 1 with
2113sigma orbitals.  Another example is movement of the core orbital to the
2114RAS1 space for core hole calculation.  In general, use of this option
2115necessitates a pre-calculation with STOP AFTER MO-ORTHONORMALIZATION and
2116identification of the various orbitals by inspection of the output.
2117
2118
2119\pagebreak[3]
2120\subsection{\label{ref-popinp}\Sec{POPULATION ANALYSIS}}
2121
2122{\bf Purpose:}
2123
2124To direct population analysis\index{population analysis} of the wave function.
2125Requires a set of natural orbitals\index{natural orbitals!population analysis} and their occupation.
2126
2127\begin{description}
2128\item[\Key{ALL}]
2129  Do all options.
2130
2131%\item[\Key{DIPMOM}]
2132%  Calculate dipole moments. Note that this requires that the dipole
2133%  length integrals are available on the file \verb|AOONEINT|.\index{dipole moment}
2134%Aug 04: not working as far as I know /hjaaj
2135
2136\item[\Key{GROSSALL}]
2137  Do all gross population analysis. Note that this requires that the dipole
2138  length integrals are available on the file \verb|AOPROPER|\index{population analysis}
2139
2140\item[\Key{GROSSMO}]
2141  Do gross MO population analysis.\index{population analysis}
2142
2143\item[\Key{MULLIKEN}]
2144  Do Mulliken population analysis\index{population analysis}\index{population analysis!Mulliken}\index{Mulliken population analysis}
2145
2146\item[\Key{NETALL}]
2147  Do all net population analysis.\index{population analysis}
2148
2149\item[\Key{NETMO}]
2150  Do net MO population analysis.\index{population analysis}
2151
2152\item[\Key{PRINT}]
2153  Default = 1\\
2154  \kw{READ (LUINP,*) IPRMUL} \\
2155  Print level for population analysis.
2156
2157%\item[\Key{QUADRP}]
2158%  Calculate quadrupole moments. Note that this requires that the quadrupole
2159%  integrals are available on the file \verb|AOONEINT|\index{quadrupole moment}
2160%Aug 04: not working as far as I know /hjaaj
2161
2162\item[\Key{VIRIAL}]\index{virial analysis} \ \\
2163  Do virial analysis.
2164\end{description}
2165
2166\pagebreak[3]
2167\subsection{\label{ref-priinp}\Sec{PRINT LEVELS}}
2168
2169{\bf Purpose:}
2170
2171To control the printing of output.
2172
2173\begin{description}
2174\item[\Key{CANONI}] \ \\
2175  Generate canonical/natural orbitals if the wave function has
2176  converged\index{canonical orbital}\index{natural orbitals}.
2177
2178\item[\Key{IPRAVE}] \ \\
2179  \kw{READ (LUINP,*) IPRAVE} \\
2180  Sets print level for routines used in "super symmetry" averaging
2181  (default is the general print level from \verb|**DALTON|).
2182
2183\item[\Key{IPRCIX}] \ \\
2184  \kw{READ (LUINP,*) IPRCIX} \\
2185  Sets print level for setup of determinant/CSF index information (default = 0).
2186  (default is the general print level from \verb|**DALTON|).
2187
2188\item[\Key{IPRCNO}] \ \\
2189  \kw{READ (LUINP,*) IPRCNO} \\
2190  Sets print level for \quotekw{.TRACI} option.
2191  To print the natural orbital occupations in each iteration set
2192  IPRCNO = 1, higher values will give more print.
2193  (default is the general print level from \verb|**DALTON| plus one).
2194
2195\item[\Key{IPRDIA}] \ \\
2196  \kw{READ (LUINP,*) IPRDIA} \\
2197  Sets print level for calculation of CI diagonal
2198  (default is the general print level from \verb|**DALTON| minus one).
2199
2200\item[\Key{IPRDNS}] \ \\
2201  \kw{READ (LUINP,*) IPRDNS} \\
2202  Sets print level for calculation of CI density matrices
2203  (default is the general print level from \verb|**DALTON|).
2204
2205%\item[\Key{IPRERR}] \ \\
2206%  \kw{READ (LUINP,*) IPRERR} \\
2207%  Sets print level for statistics in error file, LUERR (default = 1)
2208
2209\item[\Key{IPRFCK}] \ \\
2210  \kw{READ (LUINP,*) IPRFCK} \\
2211  Sets print level in the Fock matrix construction routines
2212  (default is the general print level from \verb|**DALTON|).
2213
2214\item[\Key{IPRKAP}] \ \\
2215  \kw{READ (LUINP,*) IPRKAP} \\
2216  Sets print level in routines for calculation of optimal orbital trial vectors
2217  (default is the general print level from \verb|**DALTON|).
2218
2219\item[\Key{IPRSIG}] \ \\
2220  \kw{READ (LUINP,*) IPRSIG} \\
2221  Sets print level for calculation of CI sigma vectors
2222  (default is the general print level from \verb|**DALTON|).
2223
2224\item[\Key{IPRSOL}] \ \\
2225  \kw{READ (LUINP,*) IPRSOL} \\
2226  Sets print level in the solvent contribution parts of the calculation
2227  (default is the general print level from \verb|**DALTON| plus four).
2228
2229\item[\Key{NOSUMMARY}]
2230  No final summary of calculation.
2231
2232\item[\Key{POPPRI}] \ \\
2233  \kw{READ (LUINP,*) LIM\_POPPRI} \\
2234  Print Mulliken occupation of the first LIM\_POPPRI atoms in
2235  each SCF iteration. Useful for understanding convergence.
2236  (Default = 16, corresponding to two lines of output).
2237
2238\item[\Key{PRINTFLAGS}]
2239 Default: flags set by general levels in \quotekw{\Key{PRINTLEVELS}}
2240\begin{verbatim}
2241  READ (LUINP,*) NUM6, NUM4
2242  IF (NUM6 .GT. 0) READ (LUINP,*) (NP6PTH(I), I=1,NUM6)
2243  IF (NUM4 .GT. 0) READ (LUINP,*) (NP4PTH(I), I=1,NUM4)
2244\end{verbatim}
2245  Individual print flag settings (debug option).
2246
2247\item[\Key{PRINTLEVELS}]
2248  Default: IPRI6 = 0 and IPRI4 = 5 \\
2249  \kw{READ (LUINP,*) IPRI6,IPRI4 } \\
2250  Print levels on units LUW6 and LUW4, respectively.
2251%
2252%\item[\Key{PRINTUNITS}]
2253%  \kw{READ (LUINP,*) LUW6,LUW4 } \\
2254%  Unit numbers for general output and summary output, respectively
2255%  (default: LUW4 = 6 and LUW6 = 6).
2256%
2257\item[\Key{THRPWF}] \ \\
2258  \kw{READ (LUINP,*) THRPWF} \\
2259  Threshold for printout of wave function CI coefficients (default = 0.05).
2260 \end{description}
2261
2262
2263
2264%\ifsolvent
2265\pagebreak[3]
2266\subsection{\label{ref-rhfinp}\Sec{SCF INPUT}}
2267
2268{\bf Purpose:}
2269
2270This section deals with the closed shell, one open shell and
2271high--spin spin-restricted
2272Hartree--Fock cases\index{SCF}\index{HF}\index{Hartree--Fock}
2273and Kohn-Sham DFT\index{DFT}.
2274The input here will usually only be used if either
2275\quotekw{\Key{DFT}} or \quotekw{\Key{HF}}
2276has been specified under \quotekw{\Sec{*WAVE FUNCTIONS}}
2277(though it is also needed for MP2 calculations based on saved closed-shell HF
2278orbitals).
2279High--spin spin-restricted open-shell Hartree--Fock or Kohn--Sham DFT calculations are activated by
2280using the \quotekw{.SINGLY OCCUPIED} described here.
2281Other single configuration cases with more than one open shell\index{open shell!SCF}
2282can be handled by the general \quotekw{\Key{MCSCF}} option, by appropriate specifications
2283in the \Sec{CONFIGURATION INPUT} section.
2284
2285\begin{description}
2286\item[\Key{AUTOCCUPATION}]
2287  Default for SCF calculations starting from extended H\"{u}ckel, EWMO, or H1DIAG
2288  starting orbitals.
2289
2290  Allow the distribution of the Hartree--Fock/DFT occupation numbers over
2291  symmetries\index{Hartree--Fock occupation}\index{HF occupation} to
2292  change based on changes in orbital ordering during DIIS\index{DIIS} optimization.
2293  This keyword is incompatible with \quotekw{.SINGLY OCCUPIED} and \quotekw{.COREHOLE}, or
2294  if the HF calculation is followed by CI or MCSCF.
2295
2296%\item[\Key{EDIIS}]
2297%  Use a from Kudin {\it et al.} slightly modified (E)DIIS-scheme.
2298%  Keys associated with DIIS are also valid for EDIIS (e.g. MXDIIS etc.)
2299
2300\item[\Key{C2DIIS}]
2301  Use Harrell Sellers' C2-DIIS algorithm instead of Pulay's C1-DIIS algorithm
2302  (see comments).
2303
2304\item[\Key{COREHOLE}] \ \\
2305  \kw{READ (LUINP,*) JCHSYM,JCHORB} \\
2306  JCHSYM = symmetry of core orbital\\
2307  JCHORB = the orbital in symmetry JCHSYM with a single core hole\\
2308  Single core hole\index{core hole} open shell RHF calculation, \quotekw{\Key{OPEN
2309  SHELL}} must not
2310  be specified.  The specified core orbital must be
2311  inactive\index{inactive orbital}.
2312  The number of doubly occupied orbitals in symmetry \kw{JCHSYM} will be reduced with one
2313  and instead an open shell orbital will be added for the core hole orbital.
2314  If the specified core orbital is not the last occupied orbital in symmetry
2315  \kw{JCHSYM} it will switch places with that orbital and user-defined reordering
2316  is not possible.
2317  If explicit reordering is required you must also reorder
2318  the core orbital yourself and let \kw{JCHORB} point to the last occupied orbital
2319  of symmetry \kw{JCHSYM}.  See comments below.
2320
2321\item[\Key{CORERELAX}]
2322  (ignored if \quotekw{\Key{COREHOLE}} isn't also specified)\\
2323  Optimize core hole\index{core hole} state with relaxed
2324  core\index{relaxed core} orbital using Newton-Raphson algorithm.
2325  It is assumed that this calculation follows an optimization
2326  with frozen core orbital and the specific value of
2327  \quotekw{JCHORB} under \quotekw{\Key{COREHOLE}} is ignored (no
2328  reordering will take place).
2329
2330%\item[\Key{DIRFOCK}] \ \\
2331%  Direct Fock matrix constructions (recalculate integrals when needed).
2332%  Default: AO integrals or P-supermatrix integrals read from disk.
2333%\fi
2334
2335\item[\Key{DOUBLY OCCUPIED}] \ \\
2336    \kw{READ (LUINP,*) (NRHF(I),I=1,NSYM)} \\
2337  \index{HF}\index{SCF}\index{Hartree--Fock}\index{MP2}\index{M{\o}ller-Plesset!second-order}
2338  Explicit specification of number of doubly occupied orbitals in each symmetry
2339  for DFT, RHF and MP2 calculations. This keyword
2340  is required when Hartree--Fock or MP2 is part of a multistep
2341  calculation which includes an MCSCF wave function.
2342  Otherwise the program by default will try to guess the occupation,
2343  corresponding to the  \quotekw{.AUTOCC} keyword.
2344
2345\item[\Key{ELECTRONS}] \ \\
2346  \kw{READ (LUINP,*) NRHFEL} \\
2347  Number of electrons in the molecule\index{electrons in molecule}.
2348  By default, this number will be determined on the basis of the nuclear
2349  charges and the total charge of the molecule\index{charge of molecule}
2350  as specified in the \molinp\ file.
2351  The keyword is incompatible with the keywords \quotekw{.DOUBLY OCCUPIED},
2352  \quotekw{.OPEN SHELL}, and \quotekw{.SINGLY OCCUPIED}.
2353
2354\item[\Key{FC MVO}] \ \\
2355  \kw{READ (LUINP,*) (NMVO(I), I = 1,NSYM)} \\
2356  Modified virtual orbitals using Bauschlichers suggestion
2357  (see Ref.~\cite{cwbjcp72})
2358  for CI or for start guess for MCSCF. The modified virtual orbitals
2359  are obtained by  diagonalizing the virtual-virtual
2360  block of the Fock matrix constructed from NMVO(1:NSYM) doubly
2361  occupied orbitals.
2362  The occupied SCF orbitals (i.e those specified with
2363  \quotekw{.DOUBLY OCCUPIED} and \quotekw{.OPEN SHELL}
2364  or by automatic occupation) are not modified.
2365  The construction of modified virtual orbitals
2366  will follow any SCF and MP2 calculations.
2367  See comments below.
2368
2369\item[\Key{FOCK ITERATIONS}] \ \\
2370  \kw{READ (LUINP,*) MAXFCK} \\
2371  Maximum number of closed-shell Roothaan\index{Roothaan iteration}
2372  Fock iterations (default = 0).
2373
2374\item[\Key{FROZEN CORE ORBITALS}] \ \\
2375  \kw{READ (LUINP,*) (NFRRHF(I),I=1,NSYM)} \\
2376  Frozen orbitals per symmetry (if MP2 follows then at least these orbitals
2377  must be frozen in the MP2 calculation).
2378  NOTE: no Roothaan Fock iterations allowed if frozen orbitals.
2379
2380\item[\Key{H1VIRT}] Use the virtual orbitals that diagonalize the
2381  one-electron Hamiltonian operator.
2382
2383\item[\Key{MAX DIIS ITERATIONS}] \ \\
2384  \kw{READ (LUINP,*) MXDIIS} \\
2385  Maximum number of DIIS iterations\index{iteration number!DIIS, max}\index{DIIS!max iterations} (default = 60).
2386
2387\item[\Key{MAX ERROR VECTORS}] \ \\
2388  \kw{READ (LUINP,*) MXEVC} \\
2389  Maximum number of DIIS error vectors\index{DIIS!error vectors, max}
2390  (default = 10, if there is sufficient memory available to hold these
2391  vectors in memory).
2392
2393\item[\Key{MAX MACRO ITERATIONS}] \ \\
2394  \kw{READ (LUINP,*) MXHFMA} \\
2395  Maximum number of QCSCF macro\index{iteration number!QCSCF macro, max}
2396 iterations (default = 15).
2397
2398
2399\item[\Key{MAX MICRO ITERATIONS}] \ \\
2400  \kw{READ (LUINP,*) MXHFMI} \\
2401  Maximum number of QCSCF\index{SCF!quadratic convergent} micro iterations per macro iteration (default = 12).
2402
2403\item[\Key{NODIIS}]
2404  Do not use DIIS algorithms\index{DIIS} (default: use DIIS algorithm).
2405
2406\item[\Key{NONCANONICAL}]
2407  No transformation to canonical orbitals\index{canonical orbital}.
2408
2409\item[\Key{NOQCSCF}]
2410  No quadratically convergent SCF\index{SCF!no quadratically convergent} iterations.
2411  Default is to switch to QCSCF if DIIS doesn't converge.
2412
2413\item[\Key{OPEN SHELL}]
2414  Default = no open shell\\
2415  \kw{READ (LUINP,*) IOPRHF} \\
2416  Symmetry of the open shell in a one open shell\index{open shell!HF}\index{HF!open shell}
2417  calculation. See also \quotekw{.SINGLY OCCUPIED} for high-spin ROHF with more than one
2418  singly occupied orbital.
2419
2420\item[\Key{PRINT}] \ \\
2421  \kw{READ (LUINP,*) IPRRHF} \\
2422  Resets general print level to \verb|IPRRHF| in Hartree--Fock/DFT calculations
2423  (default is the general print level from \verb|**DALTON| minus one).
2424
2425\item[\Key{SHIFT}]  \ \\
2426  \kw{READ (LUINP,*) SHFTLVL} \\
2427  Initial value of level-shift parameter in DIIS iterations.
2428  The default value is 0.0D0 (no level shift).
2429  May be tried if convergence problems in DIIS. The value is added
2430  to the diagonal of the occupied part of the Fock matrix before
2431  Roothaan diagonalization, reducing the mixing of occupied and
2432  virtual orbitals (step restriction).
2433  NOTE that the value should thus be negative.  The DIIS routines
2434  will automatically invoke level-shifting (step restriction) if
2435  DIIS seems to be stalling.
2436
2437\item[\Key{SINGLY OCCUPIED}] Default = no singly occupied orbitals \\
2438    \kw{READ (LUINP,*) (NROHF(I),I=1,NSYM)} \\
2439  High--spin spin-restricted open-shell Hartree--Fock (aka HSROHF, ROHF)
2440  or Kohn-Sham DFT (aka HSROKS, HSRODFT, RODFT, ROKS).
2441 \index{HSROHF}\index{HSRODFT}\index{HSROKS}\index{ROHF!high spin}\index{RODFT!high spin}\index{ROKS!high spin}
2442  Specify the number of singly occupied orbitals in each irreducible representation
2443  of the molecular point group. Only the high-spin state of these
2444  singly-occupied orbitals will be made and used in the calculations.
2445  We recommend to always run high-spin open-shell geometry optimizations as direct calculations
2446  (\quotekw{\Key{DIRECT}} under \quotekw{\Sec{DALTON}}),
2447  because analytical molecular gradients are only implemented for direct calculations
2448  (numerical gradients will be used for non-direct calculations).
2449
2450\item[\Key{THRESH}]
2451  Default = 1.0D-05 (1.0D-06 if MP2)\\
2452  \kw{READ (LUINP,*) THRRHF} \\
2453  Hartree--Fock/DFT convergence threshold for energy gradient.  The convergence
2454  of the energy will be approximately the square of this number.
2455
2456\end{description}
2457
2458
2459\noindent{\bf Comments:}
2460
2461By default, the RHF/DFT part of a calculation will consist of :
2462\begin{enumerate}
2463\item {MAXFCK Roothaan Fock iterations (early exit if convergence
2464    or oscillations). However, the default is that no Roothaan Fock
2465iterations are done unless explicitly requested through the keyword
2466\quotekw{.FOCK I}.
2467}
2468\item {MXDIIS DIIS iterations (exit if convergence, {\it i.e.\/} gradient norm
2469    less than THRRHF, and if convergence rate too slow or even diverging).
2470}
2471\item {Unless NOQCSCF, quadratically convergent Hartree--Fock/DFT until
2472    gradient norm less than THRRHF.
2473}
2474\item{If \quotekw{.FC MVO} has been specified
2475    then the virtual SCF orbitals will be modified by diagonalizing
2476    the virtual-virtual block of
2477    a modified Fock matrix: the Fock matrix
2478    based on the occupied orbitals specified after the keyword, a
2479    good choice is the inactive (doubly occupied) orbitals in the
2480    following CI or MCSCF.
2481    The occupied SCF orbitals will not be modified.
2482    If the RHF calculation is followed by a CI or an MCSCF calculation,
2483    \quotekw{.FC MVO} will usually provide much
2484    better start orbitals than the canonical orbitals (canonical
2485    orbitals will usually put diffuse, non-correlating orbitals in the
2486    active space). \\
2487    WARNING: if both \quotekw{.MP2} and \quotekw{.FC MVO} are specified,
2488    then the MP2 orbitals will be destroyed and replaced with \quotekw{.FC MVO}
2489    orbitals.
2490}
2491\end{enumerate}
2492
2493In general \quotekw{.DOUBLY OCCUPIED} should be specified for CI or MCSCF
2494\index{HF occupation}\index{Hartree--Fock occupation}\index{CI}\index{MCSCF}
2495\index{Configuration Interaction}
2496wave function calculations -- you anyway need to know the distribution
2497of orbitals over symmetries to specify the \quotekw{*CI INPUT} input.
2498For RHF\index{RHF}\index{SCF}\index{Hartree--Fock}
2499or MP2\index{MP2}\index{M{\o}ller-Plesset!second-order}
2500calculations the orbital occupation will be determined on the
2501basis of the nuclear charges and molecular charge of the molecule as
2502specified in the \molinp\ file.
2503
2504By default, starting orbitals and initial orbital occupation will
2505be determined automatically on the basis of a H\"{u}ckel\index{H\"{u}ckel}
2506calculation (for molecules where all nuclear charges are
2507less than or equal to 36), corresponding to the \quotekw{.AUTOCC} keyword.
2508\index{starting orbitals!SCF}\index{H\"{u}ckel!starting orbitals}.
2509If problems is experienced due to the
2510H\"{u}ckel starting guess, it can be avoided by requiring another set of
2511starting orbitals ({\it e.g.\/} \verb|H1DIAG|).
2512
2513%The default convergence threshold is quite sharp (compare with the
2514%default for MCSCF), this is done in order to have good orbitals
2515%for MP2 calculations.  For Hartree--Fock
2516%calculations with many basis functions
2517%which are not to be followed by MP2 or used for finite difference
2518%property calculations, some CPU time may be save by lowering the
2519%threshold to the minimum acceptable accuracy.
2520
2521It is our experience that
2522it is usually most efficient not to perform any Roothaan Fock iterations
2523before DIIS is activated, therefore, MAXFCK = 0 as default.
2524The algorithm described in
2525Harrell Sellers, Int. J. Quant. Chem. {\bf 45}, 31-41 (1993) is
2526also implemented, and may be selected with \quotekw{\Key{C2DIIS}}.
2527
2528
2529FC MVO: This option can be used without a Hartree--Fock calculation
2530to obtain compact virtual orbitals, but \quotekw{.DOUBLY OCCUPIED} must be
2531specified anyway in order to identify the virtual orbitals to be transformed.
2532
2533COREHOLE: Enable SCF
2534single core-hole\index{core hole} calculations. To perform
2535an SCF core hole calculation just add the \quotekw{\Key{COREHOLE}}
2536keyword to the input for the closed-shell RHF ground state
2537calculation, specifying from which orbital to remove an electron,
2538and provide the program with the ground state orbitals using the
2539appropriate \quotekw{\Key{MOSTART}} option (normally \kw{NEWORB}).
2540Note that this is different from the MCSCF version of
2541\quotekw{\Key{COREHOLE}} under \quotekw{\Sec{OPTIMIZATION}}
2542(p.~\pageref{ref-optinp}); in the MCSCF case the user must
2543explicitly move the core hole orbital from the inactive class to
2544RAS1 by modifying the \quotekw{\Sec{CONFIGURATION INPUT}}
2545(p.~\pageref{ref-wavinp}) specifications between the initial
2546calculation with filled core orbitals and the core hole
2547calculation. The core hole\index{core hole} orbital will be
2548frozen\index{frozen core hole} in the following optimization.
2549After this calculation has converged, the CORERELAX option may be
2550added and the core orbital will be relaxed\index{relaxed core hole}.
2551When CORERELAX is specified it is assumed that the
2552calculation was preceded by a frozen core calculation, and that
2553the orbital has already been moved to the open shell orbital. Only
2554the main peak can be obtained in SCF calculations, for shake-up
2555energies MCSCF must be used.
2556
2557\pagebreak[3]
2558\subsection{\label{ref-stexinp}\Sec{STEX INPUT}}
2559
2560{\bf Purpose:}
2561
2562Options for a STEX static exchange calculation.
2563(Note: A STEX calculation may require a sequence of four DALTON calculations, see the test energy\_stex for inspiration.)
2564
2565\begin{description}
2566\item[\Key{XAS}]
2567X-ray absorption spectroscopy.
2568
2569\item[\Key{XES}]
2570X-ray emission spectroscopy.
2571
2572\item[\Key{SHAKE}]
2573Electron shake-up/off spectroscopy.
2574
2575\item[\Key{AUGER}] \ \\
2576  \kw{READ (LUINP,*) NAUGER, (IAUGER(I),JAUGER(I), I=1,NAUGER)} \\
2577Auger orbital pairs.
2578
2579\item[\Key{AUGERTEST}]
2580Build RPA matrix.
2581
2582\item[\Key{PRINT}] \ \\
2583  \kw{READ (LUINP,*) IPRSTX} \\
2584Print level in STEX routines.
2585
2586\item[\Key{OPEN S}] \
2587\begin{verbatim}
2588  READ (LUINP,*) NOPEN(1:NSYM)
2589  do isym = 1, nsym
2590  if (nopen(isym) > 0) then
2591     READ (LUINP,*) IOPEN(1:NOPEN(ISYM),ISYM)
2592  end if
2593  end do
2594\end{verbatim}
2595  Open shells in STEX calculation.
2596
2597\item[\Key{COEFFI}] \
2598\begin{verbatim}
2599  do isym = 1, nsym
2600  if (nopen(isym) > 0) then
2601     READ (LUINP,*) CJ(1:NOPEN(ISYM))
2602     READ (LUINP,*) CK(1:NOPEN(ISYM))
2603  end if
2604  end do
2605\end{verbatim}
2606  Coefficients for modified J and K Fock matrices.
2607  Note: \kw{.OPEN SH} must be specified before this keyword.
2608
2609\item[\Key{AO}]
2610  Save STEX matrices in AO basis (default: save in MO basis).
2611
2612\end{description}
2613
2614
2615\pagebreak[3]
2616\subsection{\label{ref-solinp}\Sec{SOLVENT}}
2617
2618{\bf Purpose:}
2619
2620Model solvent effects with the self-consistent
2621reaction\index{reaction field} field model.
2622Any specification of dielectric constant(s)\index{dielectric constant}
2623will activate this model.
2624
2625\begin{description}
2626\item[\Key{CAVITY}]
2627  Required, no defaults.\\
2628  \kw{READ (LUINP,*) RSOLAV}\\
2629  Enter radius of spherical cavity\index{cavity!radius} in atomic units (\bohr{}).
2630
2631\item[\Key{DIELECTRIC CONSTANT}] \ \\
2632  \kw{READ (LUINP,*) EPSOL}\\
2633  Enter relevant dielectric constant\index{dielectric constant} of solvent.
2634
2635\item[\Key{INERSINITIAL}] \ \\
2636  \kw{READ (LUINP,*) EPSOL, EPPN}\\
2637  Enter the static and optical dielectric constants\index{dielectric constant} of the solvent
2638  for calculation of the initial state defining inertial polarization\index{inertial polarization}. \\
2639  Note that the optical dielectric constant specified here
2640  only will be used in case there is a calculation of response
2641  properties, for which this is an alternative input to the use of the
2642  keyword \Key{INERSFINAL}.
2643
2644\item[\Key{INERSFINAL}] \ \\
2645  \kw{READ (LUINP,*) EPSTAT,EPSOL}\\
2646  Enter the static and optical dielectric\index{dielectric constant} constants of the solvent
2647  for state specific calculation of the final state with inertial polarization
2648  from a previous calculation with \quotekw{\Key{INERSINITIAL}}\index{final polarization}.
2649  This can for example be used to optimize an excited MCSCF electronic state
2650  with inertial polarization from a previous ground state MCSCF calculation.
2651  The "\verb|SIRIFC|" file from the previous calculation with \quotekw{\Key{INERSINITIAL}}
2652  will contain information about the inertial polarization and must be provided for the
2653  \quotekw{\Key{INERSFINAL}} calculation. \\
2654  This keyword can also be used to specify the static and optical dielectric constants
2655  for non-equilibrium solvation linear, quadratic, or cubic response functions,
2656  see also Sec.~\ref{sec:solvnoneqrsp}, but this is usually easier done with
2657  \quotekw{.INERSINITIAL} (requires only one \dalton\ calculation instead of two).
2658
2659\item[\Key{MAX L}]
2660  Required, no defaults.\\
2661  \kw{READ (LUINP,*) LSOLMX}\\
2662  Enter maximum L quantum number in multipole expansion of charge
2663  distribution in cavity.
2664
2665\item[\Key{PRINT}] \ \\
2666  \kw{READ (LUINP,*) IPRSOL} \\
2667  Print level in solvent module routines
2668  (default is the general print level from \verb|**DALTON| plus four).
2669\end{description}
2670
2671\noindent{\bf Comments:}
2672
2673One and only one of \quotekw{\Key{DIELECTRIC CONSTANT}},
2674\quotekw{\Key{INERSINITIAL}}, and \quotekw{\Key{INERSFINAL}} must be
2675specified.
2676%\fi % end of \ifsolvent
2677
2678
2679
2680\pagebreak[3]
2681\subsection{\label{ref-stpinp}\Sec{STEP CONTROL}}
2682
2683{\bf Purpose:}
2684
2685User control of the NEO restricted step optimization.
2686
2687\begin{description}
2688\item[\Key{DAMPING FACTOR}]
2689  Default = 1.0D0\\
2690  \kw{READ (LUINP,*) BETA} \\
2691  Initial value of damping (BETA).\index{damping}
2692
2693\item[\Key{DECREMENT FACTOR}]
2694  Default = 0.67D0\\
2695  \kw{READ (LUINP,*) STPRED} \\
2696  Decrement factor on trust radius\index{trust radius}
2697
2698\item[\Key{GOOD RATIO}]
2699  Default = 0.8D0 \\
2700  \kw{READ (LUINP,*) RATGOD} \\
2701  Threshold ratio for good second order agreement: the trust radius can
2702  be increased if ratio is better than RATGOD.
2703
2704\item[\Key{INCREMENT FACTOR}]
2705  Default = 1.2D0\\
2706  \kw{READ (LUINP,*) STPINC} \\
2707  Increment factor on trust radius.\index{trust radius}
2708
2709\item[\Key{MAX DAMPING}]
2710  Default = 1.0D6\\
2711  \kw{READ (LUINP,*) BETMAX} \\
2712  Maximum damping value.\index{damping}
2713
2714\item[\Key{MAX STEP LENGTH}]
2715  Default = 0.7D0\\
2716  \kw{READ (LUINP,*) STPMAX} \\
2717  Maximum acceptable step length, trust radius will never be larger than
2718  STPMAX even if the ratio is good as defined by GOOD RATIO.
2719
2720\item[\Key{MIN DAMPING}]
2721  Default = 0.2D0\\
2722  \kw{READ (LUINP,*) BETMIN} \\
2723  Minimum damping value
2724
2725\item[\Key{MIN RATIO}]
2726  Default = 0.4D0 for ground state, 0.6 for excited states\\
2727  \kw{READ (LUINP,*) RATMIN} \\
2728  Threshold ratio for bad second order agreement: the trust radius is
2729  to be decreased if ratio is worse than RATMIN.
2730
2731\item[\Key{NO EXTRA TERMINATION TESTS}]
2732  Skip extra termination tests and converge micro iterations to
2733  threshold.   Normally the micro iterations are terminated if the
2734  reduced NEO matrix has more negative eigenvalues than corresponding
2735  to the desired state, because then we are in a "superglobal" region
2736  and we just want to step as quickly as possible to the region where
2737  the Hessian (and NEO matrix) has the correct structure.  Further
2738  convergence is usually wasted.
2739
2740\item[\Key{REJECT THRESHOLD}]
2741  Default = 0.25 for ground state, 0.4 for excited states\\
2742  \kw{READ (LUINP,*) RATREJ} \\
2743  Threshold ratio for unacceptable second order agreement: the step
2744  must be rejected if ratio is worse than RATREJ.
2745
2746\item[\Key{THQKVA}]
2747  Default: 8.0 for MCSCF; 0.8 for QCSCF\\
2748  \kw{READ (LUINP,*) THQKVA} \\
2749  Convergence factor for micro iterations in local (quadratic) region:
2750  THQKVA*(norm of gradient)**2
2751
2752\item[\Key{THQLIN}]
2753  Default: 0.2\\
2754  \kw{READ (LUINP,*) THQLIN} \\
2755  Convergence factor for micro iterations in global (linear) region: \\
2756  THQLIN*(norm of gradient)
2757
2758\item[\Key{THQMIN}]
2759  Default: 0.1\\
2760  \kw{READ (LUINP,*) THQMIN} \\
2761  Convergence threshold for auxiliary roots in NEO MCSCF optimization.
2762
2763\item[\Key{TIGHT STEP CONTROL}]
2764  Tight step control also for ground state calculations
2765  (tight step control is always enforced for excited states)
2766
2767\item[\Key{TOLERANCE}]
2768  Default: 1.1\\
2769  \kw{READ (LUINP,*) RTTOL} \\
2770  Acceptable tolerance in deviation of actual step from trust radius
2771  (the default value of 1.1 corresponds to a maximum of 10\% deviation).
2772
2773\item[\Key{TRUST RADIUS}]
2774  Default = STPMAX = 0.7 or, if restart, trust radius determined by previous
2775            iteration.\index{trust radius}\\
2776  \kw{READ (LUINP,*) RTRUST} \\
2777  Initial trust radius.
2778
2779\end{description}
2780
2781
2782\pagebreak[3]
2783\subsection{\label{ref-trainp}\Sec{TRANSFORMATION}}
2784
2785{\bf Purpose:}
2786
2787Transformation\index{integral transformation} of two-electron
2788integrals\index{two-electron integral} to molecular orbital
2789basis\index{molecular orbital}.
2790
2791\begin{description}
2792\item[\Key{FINAL LEVEL}] \ \\
2793  \kw{READ (LUINP,*) ITRFIN} \\
2794  Final integral transformation\index{integral transformation} level (only active if the keyword
2795  \quotekw{\Key{INTERFACE}} has been specified, or this is an \aba\ or
2796  \resp\ calculation.
2797
2798\item[\Key{LEVEL}] \ \\
2799  \kw{READ (LUINP,*) ITRLVL} \\
2800  Integral transformation level (see comments).
2801
2802\item[\Key{OLD TRANSFORMATION}]
2803  Use existing transformed integrals
2804
2805\item[\Key{PRINT}] \ \\
2806  \kw{READ (LUINP,*) IPRTRA} \\
2807  Print level in integral transformation module
2808
2809\item[\Key{RESIDENT MEMORY}] \ \\
2810  \kw{READ (LUINP,*) MWORK} \\
2811  On virtual memory computers, the transformation will run more
2812  efficiently if it can be kept within the possible resident memory
2813  size: the real memory size.  {\sir} will attempt to only use MWORK
2814  double precision words in the transformation.
2815\end{description}
2816
2817
2818\noindent{\bf Comments:}
2819
2820There are several types of integral transformations which may be
2821specified by the two transformation level keywords.
2822\begin{itemize}
2823   \item[0:] CI calculations, MCSCF gradient (default if CI, but
2824             no MCSCF specified).
2825             One index all orbitals, three indices only active
2826             orbitals.
2827
2828   \item[1:] Obsolete, do not use.
2829
2830   \item[2:] Default for MCSCF optimization. All integrals needed for {\sir}
2831             second-order MCSCF optimization, including the integrals
2832             needed to explicitly construct the diagonal of the orbital
2833             Hessian. Two indices occupied orbitals, two indices all
2834             orbitals, with some reduction for inactive indices.
2835             Both (cd/ab) and (ab/cd) are stored.
2836
2837   \item[3:] Same integrals as 2, including also the (ii/aa) and
2838             (ia/ia) integrals for exact inactive-secondary diagonal elements
2839             of the orbitals Hessian.
2840
2841   \item[4:] All integrals with minimum two occupied indices.
2842
2843   \item[5:] 3 general indices, one occupied index.  Required for MP2
2844             natural orbital analysis (the MP2 module automatically
2845             performs an integral transformation of this level).
2846
2847  \item[10:] Full transformation.
2848\end{itemize}
2849
2850
2851\pagebreak[3]
2852\subsection{\label{ref-cube}\Sec{CUBE}}
2853
2854{\bf Purpose:}
2855
2856Generates cube file\index{cube file} of total SCF electron density and/or
2857molecular orbitals after SCF calculations. The keyword \quotekw{\Key{INTERFACE}}
2858must be specified.
2859
2860\begin{description}
2861\item[\Key{DENSITY}]
2862  Generates cube file ``\kw{density.cube}'' with total SCF electron density.
2863
2864\item[\Key{HOMO}]
2865  Generates cube file ``\kw{homo.cube}'' with the information of the highest
2866occupied molecular orbitals.
2867
2868\item[\Key{LUMO}]
2869  Generates cube file ``\kw{lumo.cube}'' with the information of the lowest
2870unoccupied molecular orbitals.
2871
2872\item[\Key{MO}] \ \\
2873  \kw{READ (LUINP,*) IDX\_MO} \\
2874  Generates cube file ``\kw{mo.cube}'' with specified indices of molecular orbitals
2875by ``\kw{IDX\_MO}''. For instance, valid format is like ``1-6,7,10-12'' only including
2876digits, minus sign and comma.
2877
2878\item[\Key{FORMAT}] \ \\
2879  \kw{READ (LUINP,*) CUBE\_FORMAT} \\
2880  Specifies cube file format, only ``\kw{GAUSSIAN}'' (Gaussian cube file format,
2881see\linebreak \verb|http://www.gaussian.com/g_tech/g_ur/u_cubegen.htm|) for the
2882time being.
2883
2884\item[\Key{ORIGIN}] \ \\
2885  \kw{READ (LUINP,*) CUBE\_ORIGIN} \\
2886  Reads the coordinates (a.u.) of origin/initial point.
2887
2888\item[\Key{INCREMENT}] \ \\
2889  \kw{READ (LUINP,*) N1, X1, Y1, Z1} \\
2890  \kw{READ (LUINP,*) N2, X2, Y2, Z2} \\
2891  \kw{READ (LUINP,*) N3, X3, Y3, Z3} \\
2892  Reads the number of increments and increments (a.u.) along three running directions,
2893in which ``\kw{(X1,Y1,Z1)}'' is the slowest running direction, and ``\kw{(X3,Y3,Z3)}''
2894is the fastest running direction.
2895
2896As described at \verb|http://www.gaussian.com/g_tech/g_ur/u_cubegen.htm|, if the
2897origin/initial point is (X0,Y0,Z0), then the point at (I1,I2,I3) has coordinates:
2898
2899X-coordinate: X0+(I1-1)*X1+(I2-1)*X2+(I3-1)*X3\\
2900Y-coordinate: Y0+(I1-1)*Y1+(I2-1)*Y2+(I3-1)*Y3\\
2901Z-coordinate: Z0+(I1-1)*Z1+(I2-1)*Z2+(I3-1)*Z3
2902\end{description}
2903
2904
2905\pagebreak[3]
2906\section{\label{sec:ref-molorbinp} \Sec{*MOLORB} input module}
2907
2908If formatted input of the molecular orbitals has been specified in
2909the \Sec{ORBITAL INPUT} section, then {\sir} will attempt to find
2910the two-star label "\verb|**MOLORB|" in the input file and read
2911the orbital coefficients from the lines following this label.
2912