1\chapter{Linear and non-linear response functions, RESPONSE} 2\label{ch:response} 3 4\section{Directives for evaluation of molecular response functions}\label{sec:rspinp} 5 6The directives in the following subsections may be included in the input to \resp. 7They are organized according to the program section names in which they 8appear. 9 10\resp\ is the most general part of the code for calculating 11many different electronic linear, quadratic, or cubic molecular 12response properties based on SCF, MCSCF or CI wave functions, as well as Kohn--Sham-based time-dependent density functional theory. 13No nuclear contributions are added. 14 15If the final wave function from \Sec{*WAVE FUNCTIONS} was \Key{CI}, then 16a configuration interaction\index{Configuration Interaction!response}\index{CI!response} 17response calculation will be performed. 18This is equivalent to a CI sum-over-states\index{response!CI sum-over-states} 19calculation of response properties, 20but of course calculated directly without diagonalization of the full 21CI Hamiltonian matrix. 22 23Some of the SCF/MCSCF response properties can also be requested 24from \Sec{*PROPERTIES} input modules. 25NOTE: for such properties you should request them either here or 26in \Sec{*PROPERTIES}, otherwise you will calculate them twice! 27Usually the output is nicest in 28the \Sec{*PROPERTIES} module ({\it e.g.\/} collected in tables and in 29commonly used units, most properties are only given in atomic 30units in \resp), and nuclear contributions are included if relevant. 31Some specific properties, especially those involving nuclear derivatives, 32can only be calculated via \Sec{*PROPERTIES}. 33 34Calculations of coupled cluster response properties are performed 35by different modules and are described 36in Chapter~\ref{ch:CC} on coupled cluster calculations. 37 38In addition, SOPPA\index{SOPPA}\index{polarization propagator} 39(Second-Order Polarization Propagator approximation), 40SOPPA(CC2)\index{SOPPA(CC2)} or SOPPA(CCSD)\index{SOPPA(CCSD)} (Second 41Order Polarization Propagator Approximation with Coupled Cluster 42Singles and Doubles Amplitudes) for the calculation of linear response 43\index{linear response}\index{response!linear} 44properties and excitation energies with transition moments may be 45requested in this input section. The current implementation of the 46SOPPA method is described in Ref.~\cite{mjpekdtehjajjojcp}, of the 47SOPPA(CC2) method in Ref.~\cite{spas097} and of the SOPPA(CCSD) method 48in Ref.~\cite{soppaccsd}. Note that a SOPPA calculation requires the 49keyword \Key{SOPPA}, whereas a SOPPA(CC2) or SOPPA(CCSD) calculation 50requires the keyword \Key{SOPPA(CCSD)}. 51%M. J. Packer, E. K. Dalskov, T. Enevoldsen, H. J. Aa. Jensen, and 52%J. Oddershede, J. Chem. Phys., submitted. 53 54 55\subsection{General: \Sec{*RESPONSE}} 56 57General-purpose directives are given in the \Sec{*RESPONSE} section. 58 59After the last directive of the \Sec{*RESPONSE} input group 60should follow another {\ttfamily{**<something>}} input group 61(or \Sec{*END OF DALTON INPUT} if this was the last input to \dalton). 62 63\begin{description} 64%\item{\Key{DFT-SO}} Request that the contribution to the spin--orbit 65 %integrals are calculated for a given reference density. 66 67\item{\Key{CIS}} 68Request a CI Singles calculation, which is equivalent to invoking the 69Tamm-Dancoff approximation to RPA/TDHF (invoked by \Key{TDA}). 70 71\item{\Key{HIRPA}} 72Invoke the higher RPA approximation for the calculation of linear 73response properties\index{linear response!higher RPA}. 74This approximation is identical to that of McKoy 75and coworkers~\cite{jrtsvmjcp58,tsjrvmjcp58}. The requirements to the 76preceding wave function 77calculation is the same as for the \Key{SOPPA} keyword. 78This keyword overrides a simultaneous specification of \Key{SOPPA}. 79 80\item{\Key{INPTEST}} 81Input test. For debugging purposes only. The program stops after the 82input section. 83 84\item{\Key{MAXPHP}}\\ 85\verb|READ *, MAXPHP|\\ 86Change the maximum dimension of $H_0$ subspace. Default is 100. 87PHP is a subblock of the CI matrix which is calculated explicitly 88in order to obtain improved CI trial vectors compared to the 89straight Davidson algorithm\cite{erdjcp17}. The configurations 90corresponding to 91the lowest diagonal elements are selected, unless \Key{PHPRESIDUAL} is 92specified. MAXPHP is the maximum dimension of PHP, the 93actual dimension will be less if MAXPHP will split degenerate configurations. 94 95\item{\Key{MAXRM}}\\ 96\verb|READ *, MAXRM |\\ 97Change the maximum dimension of the reduced space. Default is 600. 98When solving a linear system of equations or an eigenvalue equation, 99the reduced space is increased by the number of 100frequencies/excitations in each iteration. For single root 101calculations this should exceed the number of iterations required. 102MAXRM should be increased if many frequencies or excitation energies 103are to be calculated. 104Sharp convergence thresholds also require 105more iterations and thus larger dimension of the reduced space. 106 107\item{\Key{NOAVDI}} 108Do not use Fock type decoupling of the two-electron density matrix. 109Add $F^ID$ instead of $(F^I+F^A)D$ to $E^{[2]}$ approximate 110orbital diagonal. Not recommended as the approximate orbital diagonal 111normally will become more different from the exact orbital diagonal. 112 113\item{\Key{NODOIT}} 114Turns off direct one-index transformation \cite{ovhahjajjcc15}. 115In this way all one-index transformed integrals are stored on disk. 116 117\item{\Key{NOITRA}} 118No two-electron integral transformation. Normally the two-electron integrals are 119transformed to MO basis in the beginning of a response calculation. In a few cases 120this is not necessary, {\it e.g.\/}, if the response part is only used for 121calculating average values of an operator, or if the transformed two-electron 122integrals have been saved from a previous response calculation (not standard). 123 124\item{\Key{OPTORB}} 125Orbital trial vectors are calculated with the optimal orbital 126trial\index{optimal orbital trial vector} vector 127algorithm \cite{tuhjahjajpjjcp84}. 128 129\item{\Key{ORBSFT}}\\ 130\verb|READ *, ORBSFT|\\ 131Change the amount for shifting the orbital 132diagonal\index{orbital diagonal Hessian} of the MCSCF Hessian. 133May be used if there is a large number of negative eigenvalues. 134Default is $10^{-4}$. 135 136\item{\Key{ORBSPC}} 137Calculation with only orbital operators. 138 139\item{\Key{PHPRESIDUAL}} 140Select configurations for PHP matrix based on largest residual 141rather than lowest diagonal elements. 142 143%\item[\Key{PROP2A}] Not yet implemented apparently. 144 145\item{\Key{SOPPA}} 146Requests the second order polarization propagator approximation 147in the linear response module. 148The SOPPA\index{SOPPA}\index{polarization propagator!SOPPA}\index{response!SOPPA} 149flag requires that 150the preceding {\sir} calculation has generated the MP2 correlation 151coefficients and written them to disk (set \Key{RUN RESPONSE} in \Sec{*DALTON} 152input as well as \Key{HF} and \Key{MP2} in \Sec{*WAVE FUNCTIONS}). See 153example input in Chapter~\ref{ch:starting}. 154 155\item{\Key{PROPAV}} \\ 156\verb|READ '(A)', LABEL|\\ 157Property average\index{property average}. 158The average value of an electronic one-electron 159operator is calculated. 160(Thus, no nuclear contributions are added.) 161The line following this option must contain the 162label of the operator given in the integral property file. 163(See section \ref{ch:hermit}.) 164 165\item{\Key{QRREST}} 166Restart quadratic response\index{quadratic response}\index{response!quadratic} 167calculation. 168It is only possible to restart regular quadratic response calculations, not those 169involving residues (as \Key{SINGLE RESIDUE}, \Key{TWO-PHOTON}, and \Key{DOUBLE RESIDUE}). 170because the restarted \dalton\ does not know the excitation energies associated with the 171residues, and the excitation energies are needed to retrieve the right records from 172the \verb|RSPVEC| file. 173% hjaaj Aug 2012: does not work when excitation energies are involved because Dalton 174% does not know them when restarting, and they are needed to get the right records from 175% the RSPVEC file. 176Requires that {\em all} needed linear response solutions % and excitation vectors 177are available on the \verb|RSPVEC| file. 178 179\item{\Key{S0MIX}} 180Sum rule is calculated in mixed representation, that is, calculate 181$N_e=\langle0\mid [r,p] \mid0\rangle$ provided that dipole length and 182velocity integrals are available on the property integral file 183(calculated with \Sec{*HERMIT} options \Key{DIPLEN} and \Key{DIPVEL}). 184The calculated quantity gives a measure of the quality of the basis 185set\index{basis set!quality}. 186 187\item{\Key{SOPPA(CCSD)}} 188Requests the second order polarization propagator approximation with 189coupled cluster singles and doubles amplitudes or the second order 190polarization propagator approximation with CC2 amplitudes in the linear 191response module. The SOPPA(CCSD)\index{SOPPA(CCSD)}\index{polarization 192propagator!SOPPA(CCSD)} 193\index{response!SOPPA(CCSD)} flag requires that the preceding coupled cluster 194calculation has generated the CC2 or CCSD amplitudes and written them 195to disk (set \Key{RUN RESPONSE} in \Sec{*DALTON} input, \Key{HF} and 196\Key{CC} in \Sec{*WAVE FUNCTIONS} and \Key{SOPPA2} 197 or \Key{SOPPA(CCSD)} in \Sec{CC INPUT}). See example input in 198Chapter~\ref{ch:starting}. 199 200\item{\Key{SOPW4}} 201Calculate explicitly the W4 term described by Oddershede {\it et 202al.\/}~\cite{jopjdycpr2}. This term is already included in the normal 203SOPPA\index{SOPPA}\index{polarization propagator!SOPPA} or 204SOPPA(CCSD)\index{SOPPA(CCSD)} result, and used mostly for comparing to older 205calculations. Note that this keyword requires that \Key{SOPPA} or 206\Key{SOPPA(CCSD)}is set. 207 208\item{\Key{TDA}} 209Invoke the Tamm-Dancoff approximation to RPA/TDHF or TDDFT. Equivalent to the 210use of \Key{CIS} on a Hartree-Fock calculation. 211 212\item{\Key{TRDQF}} 213Invoke the calculation of transition density fitted charges. Only implemented for 214\Sec{LINEAR} with \Key{SINGLE RESIDUE}. The fitted charges will be calculated for 215all \Key{ROOTS}. It requires that \Key{QFIT} has been specified in 216\Sec{*WAVE FUNCTIONS}. 217 218\item{\Key{TRPFLG}} 219Triplet flag. This option is set whenever triplet 220(spin-dependent)\index{triplet response} 221operators must be used in a response calculation 222\cite{jodlypjjcp91,ovhapjhjajthjojcp97}. 223This flag forces triplet linear response for \Sec{LINEAR}, 224both for second order properties and electronic excitations 225(without and with \Key{SINGLE RESIDUE}). 226For quadratic response, \Sec{QUADRATIC}, \Key{TRPFLG} is necessary 227whenever singlet-triplet excitations are involved, for the response function as well as for 228its residues (\Key{SINGLE RESIDUE} and \Key{DOUBLE RESIDUE}). 229See section \ref{sec:quadraticrsp} for more details. 230For cubic response triplet excitations are not implemented. 231 232\end{description} 233 234\subsection{Linear response calculation: \Sec{LINEAR} without \Key{SINGLE RESIDUE}} 235\label{sec:linearrsp} 236 237A\index{linear response}\index{response!linear} linear response 238\cite{jodlypjjcp91,pjhjajjojcp89} calculation is performed for a given 239choice of operators, 240-$\langle\!\langle A; B \rangle\!\rangle_{\omega}$. 241(Note that {\em minus} the linear response properties are written to output.) 242 243In the same \resp\ calculation these linear response properties can be calculated 244together with excitation energies 245and with long range dispersion coefficients, but not 246together with quadratic or cubic response. 247 248Excitation energies and transition properties are requested with the keyword \.Key{SINGLE RESIDUE}. 249Some keywords are specific for excitation properties, 250some keywords are specific for linear response properties. 251This subsection describes the keywords for linear response properties, 252the next subsection describes the keywords for excitation properties. 253 254\begin{description} 255 256\item{\Key{DIPLEN}} 257Add the three dipole component operators to both the $A$ and $B$ operator lists, also known as dipole length operators.\index{dipole length} 258 259\item{\Key{DIPLNX/Y/Z}} 260Sets $A$ and $B$ to the X, Y, or Z component of the dipole length operators, respectively\index{dipole length}. 261 262\item{\Key{DIPMAG}} 263Add the three angular momentum component operators to both the $A$ and $B$ operator lists.\index{angular momentum} 264 265\item{\Key{DIPMGX/Y/Z}} 266Sets $A$ and $B$ to the X, Y, or Z component of the angular momentum operators\index{angular momentum}. 267 268\item{\Key{DIPVEL}} 269Add the three dipole velocity component operators to both the $A$ and $B$ operator lists.\index{dipole velocity} 270 271\item{\Key{DIPVLX/Y/Z}} 272Sets $A$ and $B$ to the X, Y, or Z component of the dipole velocity 273operator, respectively\index{dipole velocity}. 274 275\item{\Key{FERMI}} 276Add all Fermi-contact operators 277found on the file \verb|AOPROPER| to both the $A$ and $B$ operator lists. 278The calculation of Fermi-contact operator matrices must be requested in the \Sec{*INTEGRALS} input module with \Key{FC}, 279optionally restricted to selected nuclei with \Key{SELECT}. 280 281\item{\Key{FREQUE}}\\ 282\verb|READ *, NFREQ|\\ 283\verb|READ *, FREQ(1:NFREQ)|\\ 284All linear response equations are evaluated at the \verb|NFREQ| requested 285frequencies\index{frequency}. 286Two lines following 287this option must contain 1) The number of frequencies, 2) Frequencies 288in atomic units. 289Remember to increase \Key{MAXRM} if many frequencies are specified. 290Default: only zero frequency (static calculation). 291 292\item{\Key{MAX IT}}\\ 293\verb|READ (LUCMD,*) MAXITL|\\ 294Maximum number of iterations for solving a linear response 295equation. Default is 60. 296 297\item{\Key{MAXITO}}\\ 298\verb|READ (LUCMD,*) MAXITO|\\ 299Maximum number of iterations in the optimal orbital 300algorithm\index{optimal orbital trial vector} 301\cite{tuhjahjajpjjcp84}. 302Default is 5. 303 304\item{\Key{PRINT}}\\ 305\verb|READ *,IPRLR|\\ 306Sets print level for linear response module. Default is 2. 307 308\item{\Key{PROPRT}}\\ 309\verb|READ '(A)', LABEL|\\ 310Add the operator with label \verb|LABEL| 311on the file \verb|AOPROPER| to both the $A$ and $B$ operator lists. 312(The calculation of the operator must be specified in the \Sec{*INTEGRALS} input module, 313see section \ref{ch:hermit}.) 314This keyword may be repeated for different properties. 315 316\item{\Key{PV PSO}} Sets $A$ and $B$ in the linear response function 317 to the parity-violating operator and the complete list of 318 paramagnetic spin-orbit integrals. The \Key{TRPFLG} keyword will 319 also be set by this option. 320 321\item{\Key{PV SO}} Sets $A$ and $B$ in the linear response function 322 to the parity-violating operator and the complete list of 323 paramagnetic spin-orbit integrals. The \Key{TRPFLG} keyword will 324 also be set by this option. 325 326\item{\Key{PV SO1}} Sets $A$ and $B$ in the linear response function 327 to the parity-violating operator and the one-electron spin--orbit 328 integrals. The \Key{TRPFLG} keyword will 329 also be set by this option. 330 331\item{\Key{PV SO2}} Sets $A$ and $B$ in the linear response function 332 to the parity-violating operator and the two-electron spin--orbit 333 integrals. The \Key{TRPFLG} keyword will 334 also be set by this option. 335 336\item{\Key{QUADMOM}} 337Add the six cartesian quadrupole\index{quadrupole operator} component operators 338to both the $A$ and $B$ operator lists. 339 340\item{\Key{QUADXX/XY/XZ/YY/YZ/ZZ}} 341Sets $A$ and $B$ to the XX, XY, XZ, YY, YZ, or ZZ component of the 342quadrupole\index{quadrupole operator} operator, respectively. 343 344\item{\Key{RESTLR}} 345Restart\index{restart!linear response} of response calculation. This 346can only be used if the 347operator specified is the same which was used \textit{last} in the previous 348response calculation. 349 350\item{\Key{SPIN-D}} Sets $A$ and $B$ to be all spin-dipole operators 351 found on the file \verb|AOPROPER|, {\it i.e.\/} all spin-dipole 352 operators requested in the \Sec{*INTEGRALS} input module. 353 354\item{\Key{SPIN-O}} 355Sets $A$ and $B$ to Breit-Pauli spin-orbit component operators, 356both the one- and two-electron parts\index{spin-orbit}. 357 358\item{\Key{SPNORX/Y/Z}} 359Sets $A$ and $B$ to the X, Y, or Z component of the spin--orbit 360operator, respectively\index{spin-orbit}. 361 362\item{\Key{THCLR}}\\ 363\verb|READ *, THCLR|\\ 364Relative convergence threshold for all requested linear response functions. 365Default is 1.0D-3; note that this number should be at least 10 times 366bigger than the final gradient norm in the SCF/MCSCF 367wave function optimization. The accuracy of the linear response 368properties will be quadratic in this threshold; thus the default 369corresponds to convergence to approximately 6 digits. 370 371\item{\Key{TRIPLET}} Defines $A$ and $B$ to be triplet operators. 372Will also make a simultaneous \Sec{LINEAR} \Key{SINGLE RESIDUE} calculation to 373a calculation of triplet excitation energies and transition moments. 374 375\end{description} 376 377Debug keywords 378 379\begin{description} 380 381\item{\Key{ABOCHK}} Sets up the orbital part of the $E^{\left[2\right]}$ 382 and $S^{\left[2\right]}$ used in solving the linear response 383 equation. Mainly for debugging purposes. 384 385\item{\Key{ISTOCK}} Selects the starting row in setting up the orbital 386 parts of $E^{\left[2\right]}$ 387 and $S^{\left[2\right]}$ using the keyword \Key{ABOCHK}. Default is 388 1. Mainly for debugging purposes. 389 390\item{\Key{MAXOCK}} Selects the last row in setting up the orbital 391 parts of $E^{\left[2\right]}$ 392 and $S^{\left[2\right]}$ using the keyword \Key{ABOCHK}. Default is 393 6. Mainly for debugging purposes. 394 395\item{\Key{SOPRSY}} Calculate both $\alpha_{ij}$ and $\alpha_{ji}$ to 396 test the quadratic accuracy of the calculated property. Mainly for 397 debugging purposes. 398 399\end{description} 400 401\subsection{Excitation energies calculation: \Sec{LINEAR} with \Key{SINGLE RESIDUE}} 402 403Single residues\index{single residue!linear response} of the linear 404response\index{linear response!single residue}\index{response!excitations} function is 405computed. Residues of a linear response function correspond to 406transition moments\index{transition moment!linear response} and the associated poles 407correspond to vertical electronic excitation energies. 408%\cite{jodlypjjcp91,pjhjajjojcp89} 409 410In the same \resp\ calculation these excitation properties can be calculated 411together with linear response properties 412and with long range dispersion coefficients, but not 413together with quadratic or cubic response. 414 415Required keywords: 416 417\begin{description} 418 419\item{\Key{SINGLE RESIDUE}} Required to get excitation energies, without 420this keyword the linear response function will be evaluated, see Sec.~\ref{sec:linearrsp}. 421 422\end{description} 423 424Optional keywords 425 426\begin{description} 427 428\item{\Key{CHANNEL}}\\ 429\verb|line 1: Number of channel orbitals in each symmetry|\\ 430\verb|for each symmetry:|\\ 431\verb| read index of channel orbitals this symmetry (empty line if none)|\\ 432Restricted channel RPA (HF or DFT). 433Only the specified occupied orbitals are included in the RPA matrix. 434Primarily intended for core hole RPA calculations. 435See also \Key{VIRTUAL}. 436 437\item{\Key{ECD}} 438Electronic circular dicrhoism. 439Sets $A$ and $B$ to the dipole operators,\index{dipole length} 440the dipole-velocity operators,\index{dipole velocity} 441and the angular momentum operators.\index{angular momentum} 442The needed property integrals must be requested in the \Sec{*INTEGRALS} input module. 443%The property integrals \Key{ROTSTR} must be requested in the \Sec{*INTEGRALS} input module. 444 445\item{\Key{OECD}} 446Oriented Electronic circular dichroism. 447(This option includes also all of the \Key{ECD} option.) 448Sets $A$ and $B$ to the dipole operators,\index{dipole length} 449the dipole-velocity operators,\index{dipole velocity} 450the angular momentum operators,\index{angular momentum} 451the second-order moment (Cartesian electric quadrupole 452length) operators, and 453the Cartesian electric quadrupole velocity operators. 454The needed property integrals must be requested in the \Sec{*INTEGRALS} input module. 455%The property integrals \Key{ROTSTR} and \Key{SECMOM} must be requested in the \Sec{*INTEGRALS} input module. 456 457\item{\Key{DIPLEN}} 458Sets $A$ and $B$ to the X, Y, and Z components of the dipole length operators\index{dipole length}. 459 460\item{\Key{DIPLNX/Y/Z}} 461Sets $A$ and $B$ to the X, Y, or Z component of the dipole length operators, respectively\index{dipole length}. 462 463\item{\Key{DIPMAG}} 464Sets $A$ and $B$ to angular momentum (aka magnetic dipole) operators\index{angular momentum}. 465 466\item{\Key{DIPMGX/Y/Z}} 467Sets $A$ and $B$ to the X, Y, or Z component of the angular momentum operators\index{angular momentum}. 468 469\item{\Key{DIPVEL}} 470Sets $A$ and $B$ to the dipole velocity (aka momentum) operators\index{dipole velocity}. 471 472\item{\Key{DIPVLX/Y/Z}} 473Sets $A$ and $B$ to the X, Y, or Z component of the dipole velocity 474operator, respectively\index{dipole velocity}. 475 476\item{\Key{MAX IT}}\\ 477\verb|READ *, MAXITP|\\ 478Maximum number of iterations for solving the single residue 479linear response eigenvalue equation. Default is 60. 480 481\item{\Key{MAXITO}}\\ 482\verb|READ *, MAXITO|\\ 483Maximum number of iterations in the optimal orbital 484algorithm\index{optimal orbital trial vector} 485\cite{tuhjahjajpjjcp84}. 486Default is 5. 487 488\item{\Key{NSTART}}\\ 489\verb|READ (LUCMD,*) (NPPSTV(J),J=1,NSYM)|\\ 490 The number of start vectors to be used in the 491 optimization of the transition vectors in each symmetry. By default 492 this is set equal to the number of excited states that have been 493 requested through the keyword \Key{ROOTS}. 494 It can be relevant to make the number of start vectors bigger, 495 for example if the molecule has higher symmetry than used in the 496 calculation. In this case one might need more start vectors to 497 get a representative of each symmetry. 498 499\item{\Key{NSIMUL}}\\ 500\verb|READ (LUCMD,*) (NPPSIM(J),J=1,NSYM)|\\ 501The number of eigenvectors to solve simultaneously in each 502symmetry. Normally decided automatically by the program depending on 503available memory and size of eigenvectors. 504 505\item{\Key{PRINT}}\\ 506\verb|READ *,IPRPP|\\ 507Sets print level for single residue linear response module. Default is 2. 508 509\item{\Key{PROPRT}}\\ 510\verb|READ '(A)', LABEL|\\ 511Calculate either singlet or triplet transition moments for a given operator with label; LABEL. 512(The calculation of the operator must be specified to the integral 513module, see section \ref{ch:hermit}.) 514This keyword may be repeated for different properties. 515 516\item{\Key{QUADMOM}} 517Sets $A$ and $B$ to the quadrupole\index{quadrupole operator} operators. 518 519\item{\Key{QUADXX/XY/XZ/YY/YZ/ZZ}} 520Sets $A$ and $B$ to the XX, XY, XZ, YY, YZ, or ZZ component of the 521quadrupole\index{quadrupole operator} operator, respectively. 522 523\item{\Key{RESTPP}} 524Restart\index{restart!excitation energy} of single residue response 525calculation. This can only be used if the root which is 526specified is the same which was used \textit{last} in the previous 527single residue response calculation. 528 529\item{\Key{ROOTS}}\\ 530\verb|READ *,(ROOTS(I) I=1,NSYM)|\\ 531Number of roots. The line following this option contains the number 532of excited states\index{excited state} per symmetry. Excitation 533energies\index{excitation energy} are calculated for each state and if 534any operators are given, 535symmetry-allowed transition moments\index{transition moment} are 536calculated between the 537reference state and the excited states. 538Remember to increase \Key{MAXRM} if many roots are specified. 539Default: one of each symmetry. 540 541\item{\Key{SPIN-O}} 542Sets $A$ and $B$ to spin-orbit operators\index{spin-orbit}. 543Warning: this option implies \Key{TRIPLET} and 544forces the excitations to be of triplet symmetry, 545and all operators---including 546{\it e.g.\/} \Key{DIPLEN}---will be assumed by the program to be of triplet symmetry!! 547 548\item{\Key{SPNORX/Y/Z}} 549Sets $A$ and $B$ to the X, Y, or Z component of the spin--orbit 550operator, respectively\index{spin-orbit}. 551Warning: this option implies \Key{TRIPLET} and 552forces the excitations to be of triplet symmetry, 553and all operators---including 554{\it e.g.\/} \Key{DIPLEN}---will be assumed by the program to be of triplet symmetry!! 555 556\item{\Key{THCPP}}\\ 557\verb|READ *, THCPP|\\ 558Threshold for solving the single residue linear response eigenvalue equation. 559Default is 1.0D-3; note that this number should be at least 10 times 560bigger than the final gradient norm in the SCF/MCSCF 561wave function optimization, otherwise you may encounter 562numerical problems. 563The accuracy of the pole (excitation energy) will be 564quadratic in this threshold, thus the default corresponds to approximately 5656 digits. The accuracy of transition moments will be linear in this threshold. 566 567\item{\Key{TRIPLET}} Calculate triplet excitation energies and transition moments. 568Will also make a simultaneous linear response calculation of triplet symmetry. 569 570\item{\Key{OLSEN}} 571CI trial vectors are obtained with Olsen algorithm. 572 573\item{\Key{VIRTUAL}}\\ 574\verb|Max number of virtual orbitals in each symmetry|\\ 575Only the specified virtual orbitals are included in the RPA matrix. 576Primarily intended for core hole RPA (DFT or HF) calculations, 577but works for all RPA calculations. 578See also \Key{CHANNEL}. 579 580\end{description} 581 582Debug keywords 583 584\begin{description} 585 586\item{\Key{ABCHK}} Sets up $E^{\left[2\right]}$ 587 and $S^{\left[2\right]}$ used in solving the 588 single residue linear response equation. Only for debugging purposes. 589 590\item{\Key{ABSYM}} Tests the symmetry of $E^{\left[2\right]}$ 591 and $S^{\left[2\right]}$ in the reduced space. 592 Only for debugging purposes. 593 594\item{\Key{ANTTES}} Test the antisymmetry of the single residue response 595 vector. Only for debugging purposes. 596 597\end{description} 598 599\subsection{Quadratic response calculation: \Sec{QUADRA}} 600\label{sec:quadraticrsp} 601 602Calculation of third order properties\index{properties!third order} 603 as quadratic response 604functions\index{quadratic response}\index{response!quadratic}. 605$A$, $B$, and $C$-named options refer to the operators in the quadratic 606response function 607$\langle\!\langle A;B,C \rangle\!\rangle_{\omega_b,\omega_c}$ 608\cite{ovhapjhjajthjojcp97,hhhjajpjjojcp97,haovhkpjthjcp98} 609 610The second order properties from the linear response functions 611$\langle\!\langle A;B,\rangle\!\rangle_{\omega_b}$ are also printed 612(if $A$ and $B$ operators have the same spin symmetry), 613as they can be obtained at no extra computational cost. 614 615\begin{description} 616 617\item{\Key{A2TEST}} 618Test the contributions to the quadratic response function arising from 619the $A^{\left[2\right]}$ term. Mainly for debugging purposes. 620 621\item{\Key{APROP}, \Key{BPROP}, \Key{CPROP}}\\ 622\verb|READ(LUCMD,'( BN,A,I8 )')LABEL, IRANKA|\\ 623Specify the operator $A$ and optionally its spin rank. The line following this 624keyword should be the label of the operator as it appears in the file 625AOPROPER. If the line only contains the label it is assumed to be a singlet 626operator. To explicitly specify a triplet operator the label may be followed by the number 1. All variations of spin-orbit operators are always assumed to be triplet. 627 628Note that giving the label \verb|ANGMOM|, \verb|1SPNORB|, 629\verb|2SPNORB|, or \verb|MNFSPNOR|, all the components of angular 630momentum, one-electron spin--orbit, two-electron spin--orbit or the 631atomic mean-field spin--orbit operator will be selected. 632 633By specifying the labels \verb|FERMI CO|, \verb|SPIN-DIP| or 634\verb|PSO|, all components of the Fermi contact, spin--dipole or 635paramagnetic spin--orbit integrals that can be found on the file 636\verb|AOPROPER| will be selected. These integrals are selected by the 637appropriate keywords in the \Sec{*INTEGRALS} input module. 638 639\item{\Key{ASPIN}, \Key{BSPIN}, \Key{CSPIN}}\\ 640\verb|READ(LUCMD,*)ISPINA|\\ 641Spin information for quadratic response calculations. 642The line following these options contains the spin 643rank\index{spin rank} of the excitation operators that are coupled with the 644physical operators $A$, $B$, and $C$. This means that excitation spin rank may 645be different from operator spin rank. 646This is mostly relevant for open-shell singlet response functions 647where one of physical operators may be triplet. 648Note that the meaning of this keyword is a different from Dalton2011. 649 650\item{\Key{BFREQ}, \Key{CFREQ}}\\ 651\verb|READ (LUCMD,*) NBQRFR|\\ 652\verb|READ (LUCMD,*) (BQRFR(J),J=1,NBQRFR)|\\ 653Individual specification of the frequencies $\omega_b$ and $\omega_c$. 654Input as in \Key{FREQUE} above. 655May not be used for \Key{SHG} and \Key{POCKEL}. 656May not be used together with \Key{FREQUE}. 657Default is one frequency of each type: zero (static). 658 659\item{\Key{DIPLEN}} 660Sets $A$, $B$, and $C$ to dipole operators\index{dipole length}. 661 662\item{\Key{DIPLNX/Y/Z}} 663Sets $A$, $B$, and $C$ operators to the X, Y, or Z component of the 664dipole length operators, respectively\index{dipole length}. 665 666\item{\Key{E3TEST}} 667Test the contributions to the quadratic response function arising from 668the $E^{\left[3\right]}$ and $S^{\left[3\right]}$ terms. Mainly for 669debugging purposes. 670 671\item{\Key{FREQUE}}\\ 672\verb|READ *, NFREQ|\\ 673\verb|READ *, FREQ(1:NFREQ)|\\ 674Response equations are evaluated at given 675frequencies\index{frequency!quadratic response}. Two lines 676following this option must contain 1) The number of frequencies, 2) 677Frequencies. 678For the Kerr effect only the $B$-frequency is set, 679and in other cases both $B$ and $C$-frequencies are set. 680May not be used together with \Key{BFREQ} or \Key{CFREQ}. 681Default is one frequency of each type: zero (static). 682 683\item{\Key{ISPABC}}\\ 684\verb|READ *, ISPINA,ISPINB,ISPINC|\\ 685see above, \Key{ISPINA}, \Key{ISPINB}, \Key{ISPINC} 686 687 688\item{\Key{MAX IT}} 689Maximum number of iterations for solving a linear response equation. 690Default is 60. 691 692\item{\Key{MAXITO}} 693Maximum number of iterations in the optimal 694orbital\index{optimal orbital trial vector} algorithm 695\cite{tuhjahjajpjjcp84}. 696Default is 5. 697 698\item{\Key{OPTREF}} 699Only response functions connected with optical rectification 700\index{Optical rectification}\index{response!Optical 701 rectification}\index{quadratic response!Optical rectification} 702$\beta(0; \omega,-\omega)$, are computed. 703Can be specified together with \Key{SHG} and \Key{POCKEL}. 704Frequencies must be specified with \Key{FREQUE}. 705Remember to specify operators as well, {\it e.g.\/} \Key{DIPLEN}. 706 707\item{\Key{POCKEL}} 708Only response functions connected with electro-optical 709Pockels effect\index{Pockels effect}\index{response!Pockels effect}\index{quadratic response!Pockels effect} 710$\beta(-\omega; \omega,0)$, are computed. 711Can be specified together with \Key{SHG} and \Key{OPTREF}. 712Frequencies must be specified with \Key{FREQUE}. 713Remember to specify operators as well, {\it e.g.\/} \Key{DIPLEN}. 714 715\item{\Key{PRINT}}\\ 716\verb|READ *,IPRHYP|\\ 717Print level. Default is 2. 718 719\item{\Key{REFCHK}} Only used for internal testing. 720 721\item{\Key{SHG}} 722Only response functions connected with second harmonic 723generation\index{second harmonic generation}\index{response!second harmonic generation}\index{quadratic response!second harmonic generation} 724are computed, $\beta(-2\omega,\omega,\omega)$ . 725Can be specified together with \Key{POCKEL}. 726Frequencies must be specified with \Key{FREQUE}. 727Remember to specify operators as well, {\it e.g.\/} \Key{DIPLEN}. 728 729\item{\Key{SOSHIE}} 730Analyze the calculated response equations to give the quadratic 731response spin-orbit contributions to the nuclear shielding 732constants. Will report the spin-orbit corrections to the shieldings in 733ppm. Note that this keyword will not set up the required quadratic 734response functions, only analyze the calculated results if appropriate 735quadratic response functions have been requested. 736 737\item{\Key{SOSPIN}} 738Analyze the calculated response equations to give the quadratic 739response spin-orbit contributions to the indirect spin--spin coupling 740constants. Will calculate the spin-orbit corrections to the reduced spin--spin 741coupling constants. Note that this keyword will not set up the 742required quadratic 743response functions, only analyze the calculated results if appropriate 744quadratic response functions have been requested. 745 746\item{\Key{THCLR}} 747Threshold for solving the linear response equations. 748Default is $10^{-3}$. The error in the calculated property is linear 749in this threshold. 750 751\item{\Key{TSTJEP}}\\ 752\verb|READ(LUCMD,*) IAABB|\\ 753Include only $\alpha-\alpha$ (IAABB=1) or $\alpha-\beta$ (IAABB=2) 754components of the active density in the construction of the quadratic 755response function. Mainly for debugging purposes. 756 757\item{\Key{X2TEST}} 758Test the contributions to the quadratic response function arising from 759the $X^{\left[2\right]}$ term. Mainly for debugging purposes. 760 761\end{description} 762 763\subsection{Second order transition moments: \Sec{QUADRA} with \Key{SINGLE RESIDUE}} 764 765%Calculation of third order properties as quadratic response 766%functions\index{quadratic response}\index{response!quadratic}. 767%$A, B$, and $C$-named options refer to the operators in the quadratic 768%response function 769%$\langle\!\langle A;B,C \rangle\!\rangle_{\omega_b,\omega_c}$ 770%\cite{ovhapjhjajthjojcp97,hhhjajpjjojcp97,haovhkpjthjcp98} 771 772\begin{description} 773 774\item{\Key{A2TEST}} 775Test the contributions to the quadratic response function arising from 776the $A^{\left[2\right]}$ term. Mainly for debugging purposes. 777 778\item[\Key{APROP}, \Key{BPROP}] 779Specify the operators $A$ and $B$, respectively. The line following this 780option should be the label of the operator as it appears in the file 781AOPROPER. See also Sec.\ref{sec:quadraticrsp} 782 783\item{\Key{BFREQ}, \Key{FREQUE}}\\ 784\verb|READ *, NFREQ|\\ 785\verb|READ *, FREQ(1:NFREQ)|\\ 786The frequencies $\omega_b$ in atomic units. 787Response equations are evaluated at given 788frequencies\index{frequency}. Two lines 789following this option must contain 1) The number of frequencies, 2) 790Frequencies. 791 792\item{\Key{CPPHEC}} 793Specifies a circularly polarized phosphorescence\index{circularly polarized phosphorescence} 794calculation using the effective charge approximation for the spin--orbit operator, {\it i.e.\/} 795the spin-orbit\index{spin-orbit} 796induced singlet-triplet transition\index{singlet-triplet transition}. This keyword sets up the 797calculation so that no further response input is required except \Key{ROOTS}; the 798$A$ operator is set to the dipole velocity operators\index{dipole velocity} and 799the $B$ operator is set to the effective charge spin-orbit\index{spin-orbit} 800operators. The set of effective charges is obtained from Koseki et al. 801\cite{skmsgmwsnm99,skmwsmsgjpca102} for atoms with ECP:s and Ref.\cite{skmwsmsgjpc96} for "all-electron" atoms. 802The reference state {\em must} be a singlet spin state. See also \Key{PHOSPHORESCENCE}, \Key{ECPHOS}, 803\Key{CPPHMF}, \Key{CPPHOL}, and \Key{CPPHOV}. 804 805\item{\Key{CPPHMF}} 806Specifies a circularly polarized phosphorescence\index{circularly polarized phosphorescence} 807calculation using the atomic mean-field approximation for the spin--orbit operator, {\it i.e.\/} 808the spin-orbit\index{spin-orbit} 809induced singlet-triplet transition\index{singlet-triplet transition}. This keyword sets up the 810calculation so that no further response input is required except \Key{ROOTS}; the 811$A$ operator is set to the dipole velocity operators\index{dipole velocity} and 812the $B$ operator is set to the atomic mean-field spin-orbit\index{spin-orbit} 813operators. 814The reference state {\em must} be a singlet spin state. See also \Key{PHOSPHORESCENCE}, \Key{MNFPHO}, 815\Key{CPPHEC}, \Key{CPPHOL}, and \Key{CPPHOV}. 816 817\item{\Key{CPPHOL}} 818Specifies a circularly polarized phosphorescence\index{circularly polarized phosphorescence} 819calculation, {\it i.e.\/} the spin-orbit\index{spin-orbit} 820induced singlet-triplet transition\index{singlet-triplet transition} in the length gauge. 821This keyword sets up the calculation so that no further response input is required except \Key{ROOTS}; 822the $A$ operator is set to the dipole length operators\index{dipole length} and 823the $B$ operator is set to the spin-orbit\index{spin-orbit} 824operators. \cite{ovhapjhjajthjojcp97,haovbmaqc27} 825The reference state {\em must} be a singlet spin state. See also \Key{CPPHEC}, \Key{CPPHMF} and \Key{CPPHOV}. 826 827\item{\Key{CPPHOV}} 828Specifies a circularly polarized phosphorescence\index{circularly polarized phosphorescence} 829calculation, {\it i.e.\/} the spin-orbit\index{spin-orbit} 830induced singlet-triplet transition\index{singlet-triplet transition} in the velocity gauge. 831This keyword sets up the calculation so that no further response input is required except \Key{ROOTS}; 832the $A$ operator is set to the dipole velocity operators\index{dipole velocity} and 833the $B$ operator is set to the spin-orbit\index{spin-orbit} 834operators. \cite{ovhapjhjajthjojcp97,haovbmaqc27} 835The reference state {\em must} be a singlet spin state. See also \Key{CPPHEC}, \Key{CPPHMF} and \Key{CPPHOL}. 836 837\item{\Key{DIPLEN}} 838Sets $A$ and $B$ to $x, y, z$ dipole operators\index{dipole length}. 839 840\item{\Key{DIPLNX}} 841Sets $A$ and $B$ to the $x$ dipole operator\index{dipole length}. 842 843\item{\Key{DIPLNY}} 844Sets $A$ and $B$ to the $y$ dipole operator\index{dipole length}. 845 846\item{\Key{DIPLNZ}} 847Sets $A$ and $B$ to the $z$ dipole operator\index{dipole length}. 848 849\item{\Key{DIPVEL}} 850Sets $A$ and $B$ to $x, y, z$ dipole velocity operators\index{dipole velocity}. 851 852\item{\Key{E3TEST}} 853Test the contributions to the quadratic response function arising from 854the $E^{\left[3\right]}$ and $S^{\left[3\right]}$ terms. Mainly for 855debugging purposes. 856 857\item{\Key{ECPHOS}} 858Specifies a phosphorescence\index{phosphorescence} calculation using 859the effective charge approximation for the spin--orbit operator, {\it i.e.\/} 860the spin-orbit\index{spin-orbit} 861induced singlet-triplet transition\index{singlet-triplet transition}. This keyword sets up the 862calculation so that no further response input is required except \Key{ROOTS}; the 863$A$ operator is set to the dipole operators\index{dipole length} and 864the $B$ operator 865is set to the effective charge spin-orbit\index{spin-orbit} 866operators. The set of effective charges is obtained from Koseki et al. 867\cite{skmsgmwsnm99,skmwsmsgjpca102} for atoms with ECP:s and Ref.\cite{skmwsmsgjpc96} for "all-electron" atoms. 868The reference state {\em must} be a singlet spin state. See also \Key{PHOSPHORESCENCE} 869 870\item{\Key{ISPABC}}\\ 871\verb|READ *, ISPINA,ISPINB,ISPINC|\\ 872Spin symmetry of excitation operators associated with physical operators $A$ (ISPINA) and $B$ (ISPINB), 873and the excited states specified with \Key{ROOTS} (ISPINC): "0" for singlet and "1" for triplet. 874Default is "0,0,0", {\it i.e.\/} all of singlet spin symmetry. 875c.f. the same keyword in section \ref{sec:quadraticrsp}. 876{\bf Note: triplet operators are only implemented for singlet reference states.} 877%hjaaj June 2001: .ASPIN etc. should be defined for .SINGLE 878%\item[\Key{ASPIN}, \Key{BSPIN}, \Key{CSPIN}] 879%\index{quadratic response}\index{response!quadratic} 880%Spin information for quadratic response calculations. 881%The line following these options contains the spin 882%rank\index{spin rank} of the operators 883%$A$, $B$, and $C$, respectively, 0 for singlet operators and 1 for triplet 884%operators. If \Key{SINGLE} is specified, \Key{CSPIN} denotes the 885%spin of the excited state. If \Key{DOUBLE} is specified, 886%both \Key{BSPIN} and \Key{CSPIN} denote excited state spins. 887%In a triplet response calculations two of these operators are of rank one, 888%and the remaining operator of rank zero. 889 890\item{\Key{MAXITL}} 891Maximum number of iterations for linear equations in this section. 892Default is 60. 893 894\item{\Key{MAXITP}} 895Maximum number of iterations in solving the linear 896response\index{linear response}\index{response!linear} eigenvalue 897equations. 898Default is 60. 899 900\item{\Key{MAXITO}} 901Maximum number of iterations in the optimal 902orbital\index{optimal orbital trial vector} algorithm 903\cite{tuhjahjajpjjcp84}. 904Default is 5. 905 906\item{\Key{MCDBTERM}} 907Specifies the calculation of all individual components to the 908${\cal{B}}(0\to f)$ term of magnetic circular dichroism 909(MCD)\index{magnetic circular dichroism}\index{B-term}\index{MCD}. 910This keyword sets up the calculation so that no further response input is required except \Key{ROOTS}. 911The $A$ operator is set equal to the $\alpha$ component of dipole 912operator\index{dipole length} and 913the $B$ operator to the $\beta$ component of the angular momentum\index{angular momentum} 914operator. The resulting "mixed" two-photon transition moment to state $f$ 915is then multiplied the dipole-allowed one-photon transition moment 916from state $f$ (for the $\gamma$ component, with $\alpha \neq \beta \neq \gamma$). 917\cite{Coriani:MCDRSP} 918 919\item{\Key{MNFPHO}} 920Specifies a phosphorescence\index{phosphorescence} calculation using 921the atomic mean-field approximation for the spin--orbit operator, {\it i.e.\/} 922the spin-orbit\index{spin-orbit} 923induced singlet-triplet transition\index{singlet-triplet transition}. This keyword sets up the 924calculation so that no further response input is required except \Key{ROOTS}; the 925$A$ operator is set to the dipole operators\index{dipole length} and 926the $B$ operator 927is set to the atomic mean-field spin-orbit\index{spin-orbit} 928operators. 929The reference state {\em must} be a singlet spin state. See also \Key{PHOSPHORESCENCE} 930 931\item{\Key{PHOSPHORESCENCE}} 932Specifies a phosphorescence\index{phosphorescence} calculation, {\it i.e.\/} 933the spin-orbit\index{spin-orbit} 934induced singlet-triplet transition\index{singlet-triplet transition}. This keyword sets up the 935calculation so that no further response input is required except \Key{ROOTS}; the 936$A$ operator is set to the dipole length operators\index{dipole length} and 937the $B$ operator is set to the spin-orbit\index{spin-orbit} 938operators. \cite{ovhapjhjajthjojcp97,haovbmaqc27} 939The reference state {\em must} be a singlet spin state. 940 941\item{\Key{PHOSPV}} 942Specifies a phosphorescence\index{phosphorescence} calculation, {\it i.e.\/} 943the spin-orbit\index{spin-orbit} 944induced singlet-triplet transition\index{singlet-triplet transition} in the velocity gauge. 945This keyword sets up the calculation so that no further response input is required except \Key{ROOTS}; 946the $A$ operator is set to the dipole velocity operators\index{dipole velocity} and 947the $B$ operator is set to the spin-orbit\index{spin-orbit} 948operators. \cite{ovhapjhjajthjojcp97,haovbmaqc27} 949The reference state {\em must} be a singlet spin state. 950 951\item{\Key{PRINT}}\\ 952\verb|READ *,IPRSMO|\\ 953Print level. Default is 2. 954 955\item{\Key{ROOTS}}\\ 956\verb|READ *,(ROOTS(I) I=1,NSYM)|\\ 957Number of roots. The line following this option contains the number 958of excited states\index{excited state!second order moment} per symmetry. Excitation 959energies\index{excitation energy!second order moment} are calculated for each state and if 960any operators are given, 961symmetry-allowed second order transition moments\index{transition moment!second order} are 962calculated between the 963reference state and the excited states. 964Remember to increase \Key{MAXRM} if many frequencies are specified. 965 966\item{\Key{SINGLE RESIDUE}} 967Required to 968compute the single residue\index{single residue!quadratic response} of the quadratic 969response function\index{quadratic response!single residue}\index{response!quadratic, single residue}. 970For the case of dipole operators this corresponds to two-photon 971transition 972moments\index{two-photon!transition moment}\index{transition moment}\index{transition moment!two-photon}. 973 974\item{\Key{THCLR}}\verb| |\newline 975\verb|READ *, THCLR|\\ 976Threshold for solving the linear response equations. 977Default is $10^{-3}$. 978 979\item{\Key{THCPP}}\\ 980\verb|READ *, THCPP|\\ 981Threshold for solving the linear response 982\index{linear response}\index{response!linear} 983eigenvalue equation. Default is $10^{-3}$. 984 985\item{\Key{TPCD}} 986Sets up the calculation of the tensor components of the two-photon circular dichroism rotatory 987strength according to \cite{Rizzo:TPACD}, the TI equation. 988The tensor components are computed for all the excited states 989requested by the keyword \Key{ROOTS}, calculating the necessary 990quadratic response functions using the half-frequency of the 991excitation energy to the given state. The calculation path is identical to the 992one requested by \Key{TWO-PHOTON}, except that different operators are used. 993Please ignore the \mbox{***~FINAL~RESULTS~FROM~TWO-PHOTON~CALCULATION~***} output 994at the bottom of the output file when running TPCD. 995Do not forget to set \Key{DIPVEL}, \Key{ANGMOM} and \Key{ROTSTR} in **INTEGRAL 996input section. 997 998 999\item{\Key{TWO-PHOTON}} 1000Sets up the calculation of the two-photon transition strengths. This 1001calculates two-photon transition strengths for all the excited states 1002requested by the keyword \Key{ROOTS}, calculating the necessary quadratic response functions using the half-frequency of the 1003excitation energy to the given state. 1004 1005\item{\Key{X2TEST}} 1006Test the contributions to the quadratic response function arising from 1007the $X^{\left[2\right]}$ term. Mainly for debugging purposes. 1008\end{description} 1009 1010 1011\subsection{Transition moments between excited states: \Sec{QUADRA} with \Key{DOUBLE RESIDUE}} 1012 1013Required keywords: 1014 1015\begin{description} 1016 1017\item{\Key{DOUBLE RESIDUE}}\\ 1018Compute double residues\index{quadratic response!double residue} of quadratic 1019response functions\index{double residue!quadratic response}\index{response!quadratic, double residue}. 1020Double residues of the quadratic response function correspond to transition 1021moments between excited states\index{transition moment!between excited states}, 1022$\langle B \mid A \mid C \rangle$. 1023 1024\end{description} 1025 1026\noindent Optional keywords 1027 1028\begin{description} 1029 1030\item{\Key{A2TEST}} 1031Test the contributions to the quadratic response function arising from 1032the $A^{\left[2\right]}$ term. Mainly for debugging purposes. 1033 1034\item{\Key{DIPLEN}} 1035Sets $A$ to dipole operators\index{dipole length}. 1036 1037\item{\Key{DIPLNX}} 1038Sets $A$ to the $x$ dipole operator\index{dipole length}. 1039 1040\item{\Key{DIPLNY}} 1041Sets $A$ to the $y$ dipole operator\index{dipole length}. 1042 1043\item{\Key{DIPLNZ}} 1044Sets $A$ to the $z$ dipole operator\index{dipole length}. 1045 1046\item{\Key{DIPMAG}} 1047Sets $A$ to angular momentum operators\index{angular momentum}. 1048 1049\item{\Key{DIPMGX/Y/Z}} 1050Sets $A$ to the $x$, $y$, or $z$ component of the angular momentum operators\index{angular momentum}. 1051 1052\item{\Key{DIPVEL}} 1053Sets $A$ to the dipole velocity operators\index{dipole velocity}. 1054 1055\item{\Key{DIPVLX/Y/Z}} 1056Sets $A$ to the $x$, $y$, or $z$ component of the dipole velocity 1057operator, respectively\index{dipole velocity}. 1058 1059\item{\Key{E3TEST}} 1060Test the contributions to the quadratic response function arising from 1061the $E^{\left[3\right]}$ and $S^{\left[3\right]}$ terms. Mainly for 1062debugging purposes. 1063 1064\item{\Key{EXMTES}} 1065Test that the transition moment is symmetric, {\it i.e.\/} that 1066$\left<i\left|A\right|j\right> = 1067\left<j\left|A\right|i\right>$. Mainly for debugging purposes. 1068 1069\item{\Key{IPREXM}}\\ 1070\verb|READ *,IPREXM|\\ 1071Print level for special excited state transition moment routines. 1072 1073\item{\Key{ISPABC}}\\ 1074\verb|READ *, ISPINA,ISPINB,ISPINC|\\ 1075Spin symmetry of excitation operators associated with physical operator $A$ (ISPINA) 1076and the left and right excitation operators (ISPINB and ISPINC) defined to 1077generate excited states defined in given in by \Key{ROOTS}: 1078"0" for singlet and "1" for triplet. 1079C.f. the same keyword in section \ref{sec:quadraticrsp}. 1080Default is "0,0,0", {\it i.e.\/} all of singlet spin symmetry. 1081{\bf Note: triplet operators are only implemented for singlet reference states.} 1082%hjaaj June 2001: .ASPIN etc. should be defined for .DOUBLE 1083%\item[\Key{ASPIN}, \Key{BSPIN}, \Key{CSPIN}] 1084%\index{quadratic response}\index{response!quadratic} 1085%Spin information for quadratic response calculations. 1086%The line following these options contains the spin 1087%rank\index{spin rank} of the operators 1088%$A$, $B$, and $C$, respectively, 0 for singlet operators and 1 for triplet 1089%operators. If \Key{SINGLE} is specified, \Key{CSPIN} denotes the 1090%spin of the excited state. If \Key{DOUBLE} is specified, 1091%both \Key{BSPIN} and \Key{CSPIN} denote excited state spins. 1092%In a triplet response calculations two of these operators are of rank one, 1093%and the remaining operator of rank zero. 1094 1095\item{\Key{MAX IT}} 1096Maximum number of iterations for solving linear response 1097eigenvalue equation in this section. 1098 1099\item{\Key{MAXITO}} 1100Maximum number of iterations in the optimal 1101orbital\index{optimal orbital trial vector} algorithm 1102\cite{tuhjahjajpjjcp84}. 1103Default is 5. 1104 1105\item{\Key{PRINT}}\\ 1106\verb|READ *,IPRPP|\\ 1107Print level for solving linear response eigenvalue equations. 1108 1109\item{\Key{PROPRT}} 1110Specify another $A$ operator. \\ 1111The line following this 1112option should be the label of the operator as it appears in the file 1113AOPROPER. This option may be repeated for different property operators. 1114%hjaaj June 2001, ought to define as well: \item[\Key{APROP}] 1115 1116\item{\Key{QUADMOM}} 1117Sets $A$ to the quadrupole\index{quadrupole operator} operators. 1118 1119\item{\Key{QUADXX/XY/XZ/YY/YZ/ZZ}} 1120Sets $A$ to the XX, XY, XZ, YY, YZ, or ZZ component of the 1121quadrupole\index{quadrupole operator} operator, respectively. 1122 1123\item{\Key{ROOTS}}\\ 1124\verb|READ (LUCMD,*) (NPPCNV(J),J=1,NSYM)|\\ 1125Number of roots (excited states) to converge for each spatial symmetry.\\ 1126Used for $\langle B \mid$ as well as for $ \mid C \rangle$, 1127singlet or triplet as specified by \Key{ISPABC}.\\ 1128Default: one root for each symmetry. 1129 1130\item{\Key{SPIN-O}} 1131Sets $A$ to spin-orbit operators\index{spin-orbit}. 1132Warning: this option implies \Key{TRIPLET} and 1133forces the excitations to be of triplet symmetry, 1134and all operators---including 1135{\it e.g.\/} \Key{DIPLEN}---will be assumed by the program to be of triplet symmetry!! 1136 1137\item{\Key{SPNORX/Y/Z}} 1138Sets $A$ to the X, Y, or Z component of the spin--orbit 1139operator, respectively\index{spin-orbit}. 1140Warning: this option implies \Key{TRIPLET} and 1141forces the excitations to be of triplet symmetry, 1142and all operators---including 1143{\it e.g.\/} \Key{DIPLEN}---will be assumed by the program to be of triplet symmetry!! 1144 1145\item{\Key{THCPP}}\\ 1146\verb|READ *, THCPP|\\ 1147Threshold for solving the linear response 1148eigenvalue equation. Default is $10^{-3}$. 1149 1150\item{\Key{X2TEST}} 1151Test the contributions to the quadratic response function arising from 1152the $X^{\left[2\right]}$ term. Mainly for debugging purposes. 1153\end{description} 1154 1155 1156\subsection{Cubic response calculation: \Sec{CUBIC}} 1157Calculation of fourth-order properties as cubic response functions\index{cubic response}\index{response!cubic} 1158\cite{pndjovhacpl242,djpnhajcp105,pndjhapdkrthhkcpl253}. 1159$A,B$,$C$, and $D$-named options refer to the operators in the cubic 1160response function 1161$\langle\!\langle A;B,C,D \rangle\!\rangle_{\omega_b,\omega_c,\omega_d}$ 1162 1163\begin{description} 1164 1165\item[\Key{APROP}, \Key{BPROP}, \Key{CPROP}, \Key{DPROP}] 1166Specify the operators $A$, $B$, $C$, and $D$. The line following this 1167option should be the label of the operator as it appears in the file 1168AOPROPER. 1169 1170\item[\Key{BFREQ}, \Key{CFREQ}, \Key{DFREQ}] 1171The frequencies\index{frequency!cubic response} 1172$\omega_b$, $\omega_c$, and $\omega_d$, respectively. Input as in 1173\Key{FREQUE}. 1174 1175\item{\Key{DC-SHG}} 1176Only response functions connected to the static electric field-induced 1177second harmonic generation\index{electric field!induced SHG} are computed, 1178$\gamma(-2\omega;\omega,\omega,0)$. 1179 1180\item{\Key{DC-KERR}} 1181Only response functions connected to the static electric field induced 1182Kerr effect\index{electric field!induced Kerr} are computed, 1183$\gamma(-\omega;\omega,0,0)$. 1184 1185\item{\Key{DIPLEN}} 1186Sets $A$, $B$, $C$, and $D$ to dipole operators\index{dipole length}. 1187 1188\item{\Key{DIPLNX}} 1189Sets $A$, $B$, $C$, and $D$ to the $x$ dipole operator\index{dipole length}. 1190 1191\item{\Key{DIPLNY}} 1192Sets $A$, $B$, $C$, and $D$ to the $y$ dipole operator\index{dipole length}. 1193 1194\item{\Key{DIPLNZ}} 1195Sets $A$, $B$, $C$ and $D$ to the $z$ dipole operator\index{dipole length}. 1196 1197\item{\Key{FREQUE}}\\ 1198\verb|READ *, NFREQ|\\ 1199\verb|READ *, FREQ(1:NFREQ)|\\ 1200Sets the frequencies\index{frequency!cubic response} whenever a optical process is specified. 1201Can also be used for the residue calculation and in which case 1202both $\omega_b$ and $\omega_c$ for the single residue and only 1203$\omega_b$ for the double residue. 1204 1205\item{\Key{IDRI }} 1206Only response functions connected to the intensity dependent 1207refractive\index{refractive index!intensity dependent} index are computed, 1208$\gamma(-\omega;\omega,-\omega,\omega)$. 1209 1210\item{\Key{INVEXP}} Solve the linear set of equations for the 1211 second-order perturbed wave function through explicit matrix 1212 inversion. Mainly for debugging purposes. 1213 1214\item{\Key{ISPABC}}\\ 1215\verb|READ *, ISPINA,ISPINB,ISPINC|\\ 1216Spin symmetry of $A$, $B$, $C$, and $D$-operators (ISPINA/B/C/D), 1217"0" for singlet and "1" for triplet. Note that currently only singlet 1218triplet response functions have been implemented. Do not use. 1219 1220\item{\Key{MAX IT}} 1221Maximum number of iterations for solving linear equations, default value is 60. 1222 1223\item{\Key{MAXITO}} 1224Maximum number of optimal orbital trial vector microiterations, 1225default value is 5. 1226 1227\item{\Key{PRINT}} 1228Print flag for output, default value is 2. Timer information is printed 1229out if print flag greater than 5. Response vectors printed out if 1230print flag greater than 10. 1231 1232\item{\Key{THCLR}} 1233Threshold for convergence of response vectors, default value is $10^{-3}$. 1234 1235\item{\Key{THG }} 1236Only response functions connected to the third harmonic 1237generation\index{third harmonic generation} are 1238computed, $\gamma(-3\omega;\omega,\omega,\omega)$ \cite{djpnylhajcp105}. 1239 1240\item{\Key{THRNRM}} 1241Threshold for norm of property vector $X^{[1]}$ to be considered to be 1242greater than zero in order to solve the linear 1243equation \\ 1244$\left( E^{[2]} - S^{[2]} \right)N^{X} = X^{[1]}$, default 1245value is $10^{-9}$. 1246 1247%hjaaj June 2001: is triplet tested ?? (was not listed in dalton1.1 manual) 1248%item{\Key{ISABCD}}\\ 1249%verb|READ *, ISPINA,ISPINB,ISPINC,ISPIND|\\ 1250 1251%hjaaj June 2001 1252%\Key{INVEXP} is a programmers test option 1253 1254\end{description} 1255 1256\subsection{Third-order transition moments: \Sec{CUBIC} with \Key{SINGLE RESIDUE}} 1257Calculation of single residues\index{single residue!cubic response} of 1258cubic response functions\index{cubic response!single residue}\index{response!cubic, single residue} 1259\cite{pndjovhacpl242,djpnhajcp105,pndjhapdkrthhkcpl253}. 1260$A,B$,$C$, and $D$-named options refer to the operators in the cubic 1261response function 1262$\langle\!\langle A;B,C,D \rangle\!\rangle_{\omega_b,\omega_c,\omega_d}$ 1263 1264\begin{description} 1265 1266\item[\Key{APROP}, \Key{BPROP}, \Key{CPROP}] 1267Specify the operators $A$, $B$, and $C$, respectively. 1268The line following this 1269option should be the label of the operator as it appears in the file 1270AOPROPER. 1271 1272\item[\Key{BFREQ}, \Key{CFREQ}] 1273The frequencies\index{frequency!cubic response single residue} 1274$\omega_b$ and $\omega_c$, respectively. Input as in 1275\Key{FREQUE}. 1276 1277\item{\Key{DIPLEN}} 1278Sets $A$, $B$, $C$, and $D$ to dipole operators\index{dipole length}. 1279 1280\item{\Key{DIPLNX}} 1281Sets $A$, $B$, $C$, and $D$ to the $x$ dipole operator\index{dipole length}. 1282 1283\item{\Key{DIPLNY}} 1284Sets $A$, $B$, $C$, and $D$ to the $y$ dipole operator\index{dipole length}. 1285 1286\item{\Key{DIPLNZ}} 1287Sets $A$, $B$, $C$ and $D$ to the $z$ dipole operator\index{dipole length}. 1288 1289\item{\Key{FREQUE}}\\ 1290\verb|READ *, NFREQ|\\ 1291\verb|READ *, FREQ(1:NFREQ)|\\ 1292Sets the frequencies\index{frequency!cubic response} whenever a optical process is specified. 1293Can also be used for the residue calculation in which case it sets 1294both $\omega_b$ and $\omega_c$ for the single residue and only 1295$\omega_b$ for the double residue. 1296 1297\item{\Key{MAX IT}} 1298Maximum number of iterations for solving linear equations, default value is 60. 1299 1300\item{\Key{MAXITO}} 1301Maximum number of optimal orbital trial vector microiterations, 1302default value is 5. 1303 1304\item{\Key{MAXITP}} 1305Maximum number of iteration for solving eigenvalue equation, default 1306value is 60. 1307 1308\item{\Key{NOHG}} Do not restrict the calculation to the 'harmonic 1309 generation case', that is, allow a different number and different 1310 numerical values for the frequencies of the $B$ and $C$ 1311 operators. By default, it is assumed that the $B$ and $C$ operator 1312 frequencies are identical. 1313 1314\item{\Key{PRINT}} 1315Print flag for output, default value is 2. Timer information is printed 1316out if print flag greater than 5. Response vectors printed out if 1317print flag greater than 10. 1318 1319\item{\Key{ROOTS}} 1320\verb|READ (LUCMD,*) (NTMCNV(J),J=1,NSYM)|\\ 1321Number of roots (excited states) to converge for each spatial symmetry. \\ 1322Default: one of each symmetry. 1323 1324\item{\Key{SINGLE}} 1325Computes the single residue\index{single residue!cubic response} of the cubic 1326response function\index{cubic response!single residue}. 1327In the case of dipole operators this corresponds to 1328three-photon absorption\index{three-photon!absorption}. 1329 1330\item{\Key{THCLR}} 1331Threshold for convergence of response vectors, default value is $10^{-3}$. 1332 1333\item{\Key{THCPP}} 1334Threshold for convergence of eigenvector, default value is $10^{-3}$. 1335 1336\item{\Key{THREE-PHOTON}} 1337Sets up the calculation of the three-photon transition strengths. This 1338calculates two-photon transition strengths for all the excited states 1339requested by the keyword \Key{ROOTS}, calculating the necessary 1340cubic response functions using a third of the frequency of the 1341excitation energy to the given state. 1342 1343\end{description} 1344 1345 1346\subsection{Second order moments between excited states and excited state polarizabilities: 1347\Sec{CUBIC} with \Key{DOUBLE RESIDUE}} 1348Calculation of double residues\index{double residue!cubic response} of 1349cubic response functions\index{cubic response!double residue}\index{response!cubic, double residue} 1350\cite{pndjovhacpl242,djpnhajcp105,pndjhapdkrthhkcpl253}. 1351$A,B$,$C$, and $D$-named options refer to the operators in the cubic 1352response function 1353$\langle\!\langle A;B,C,D \rangle\!\rangle_{\omega_b,\omega_c,\omega_d}$. 1354$C$ and $D$ refer to the left hand state and right hand state 1355after the double residue has been taken. 1356 1357Excited state polarizabilites are only calculated if one or more of the keywords 1358\Key{DIPLEN}, \Key{DIPLNX}, \Key{DIPLNY}, and \Key{DIPLNZ} 1359are specified. 1360Only singlet excitations and singlet property operators are implemented. 1361 1362\begin{description} 1363 1364\item[\Key{APROP}, \Key{BPROP}] 1365Specify the operators $A$ and $B$, respectively. The line following this 1366option should be the label of the operator as it appears in the file 1367AOPROPER. These two keywords can be repeated for different properties. 1368 1369\item[\Key{BFREQ}] 1370The frequencies\index{frequency!cubic response} 1371$\omega_b$. Input as in \Key{FREQUE}. 1372Default only zero frequency (static). 1373 1374\item{\Key{DIPLEN}} 1375Sets $A$ and $B$ to all three dipole component operators\index{dipole length}. 1376 1377\item{\Key{DIPLNX}} 1378Sets $A$ and $B$ to the $x$ dipole operator\index{dipole length}. 1379 1380\item{\Key{DIPLNY}} 1381Sets $A$ and $B$ to the $y$ dipole operator\index{dipole length}. 1382 1383\item{\Key{DIPLNZ}} 1384Sets $A$ and $B$ to the $z$ dipole operator\index{dipole length}. 1385 1386\item{\Key{DOUBLE}} 1387REQUIRED. 1388Computes the double\index{double residue} residue of the cubic 1389response function\index{cubic response}\index{response!cubic}. 1390In the case of dipole operators this corresponds to excited 1391state polarizabilities and two-photon transition 1392moments\index{two-photon!transition moment!excited states}\index{excited state!polarizability} 1393between excited states \cite{djpnylhajcp105}. 1394 1395\item{\Key{FREQUE}}\\ 1396\verb|READ *, NFREQ|\\ 1397\verb|READ *, FREQ(1:NFREQ)|\\ 1398Sets the frequencies\index{frequency!cubic response} whenever a optical process is specified. 1399Can also be used for the residue calculation and it does then set 1400both $\omega_b$ and $\omega_c$ for the single residue and only 1401$\omega_b$ for the double residue. 1402Default only zero frequency (static). 1403 1404\item{\Key{MAX IT}} 1405Maximum number of iterations for solving linear equations, default value is 60. 1406 1407\item{\Key{MAXITO}} 1408Maximum number of optimal orbital trial vector microiterations, 1409default value is 5. 1410 1411\item{\Key{MAXITP}} 1412Maximum number of iteration for solving eigenvalue equation, default 1413value is 20. 1414 1415\item{\Key{PRINT}} 1416Print flag for output, default value is 2. Timer information is printed 1417out if print flag greater than 5. Response vectors printed out if 1418print flag greater than 10. 1419 1420\item{\Key{ROOTS}} 1421\verb|READ (LUCMD,*) (NTMCNV(J),J=1,NSYM)|\\ 1422Number of roots (excited states) to converge for each spatial symmetry.\\ 1423Used for $<C|$ as well as for $|D>$.\\ 1424Default: one of each symmetry. 1425 1426\item{\Key{THCLR}} 1427Threshold for convergence of $A$ response vectors, default value is $10^{-3}$. 1428 1429\item{\Key{THCPP}} 1430Threshold for convergence of excitation eigenvectors, default value is $10^{-3}$. 1431 1432\end{description} 1433 1434\subsection{Module for C6, C8, C10 coefficients and more\Sec{C6}} 1435 1436 1437\begin{description} 1438 1439\item{\Key{C6ATM}, \Key{C8ATM}, \Key{C10ATM}} 1440\Key{C6ATM}, \Key{C8ATM}, \Key{C10ATM} do the same as \Key{C6SPH} etc. for 1441atoms. Only $M_L=0$ is 1442calculated and written to file (all $M_L$ values give same multipole moment 1443for atoms). 1444 1445\item{\Key{C6LMO}, \Key{C8LMO}, \Key{C10LMO}} 1446\Key{C6LMO}, \Key{C8LMO}, \Key{C10LMO} is \Key{C6SPH} etc. for linear 1447molecules\index{linear molecule}. Only 1448multipole moments\index{multipole moment} with zero or positive $M_L$ 1449are calculated and written to file. 1450 1451\item{\Key{C6SPH}, \Key{C8SPH}, \Key{C10SPH}} 1452Specification of one of \Key{C6SPH}, \Key{C8SPH}, \Key{C10SPH} 1453calculates and writes to a formatted interface file (RESPONSE.C8) the spherical multipole 1454moments in the specified/default grid points needed for C6, C8, and C10 1455coefficients, respectively ($L=1$, $L=1,2,3$, or $L=1,2,3,4,5$; 1456all for $M_L = -L,\ldots,0,\ldots,L$). 1457 1458\item{\Key{DIPLEN}} 1459Sets $A$ and $B$ to dipole operators\index{dipole length}. 1460 1461\item{\Key{DIPLNX/Y/Z}} 1462Sets $A$ and $B$ to the X, Y, or Z component of the dipole length operators, respectively\index{dipole length}. 1463 1464\item{\Key{DIPMAG}} 1465Sets $A$ and $B$ to angular momentum operators\index{angular momentum}. 1466 1467\item{\Key{DIPMGX/Y/Z}} 1468Sets $A$ and $B$ to the X, Y, or Z component of the angular momentum operators\index{angular momentum}. 1469 1470\item{\Key{DIPVEL}} 1471Sets $A$ and $B$ to the dipole velocity operators\index{dipole velocity}. 1472 1473\item{\Key{DIPVLX/Y/Z}} 1474Sets $A$ and $B$ to the X, Y, or Z component of the dipole velocity 1475operator, respectively\index{dipole velocity}. 1476 1477\item{\Key{FREQUE}}\\ 1478\verb|READ *, NCFREQ|\\ 1479\verb|READ *, CFREQ(1:NCFREQ)|\\ 1480Response equations are evaluated at given 1481frequencies\index{frequency}. Two lines following 1482this option must contain 1) The number of frequencies, 2) Frequencies 1483in atomic units. 1484 1485\item{\Key{GSLEGN}} Use a Gauss--Legendre grid for calculating imaginary polarizabilities. 1486 1487\item{\Key{MAX IT}}\\ 1488\verb|READ (LUCMD,*) MAXITC|\\ 1489Maximum number of iterations for solving a linear response 1490equation. Default is 60. 1491 1492\item{\Key{MAXITO}}\\ 1493\verb|READ (LUCMD,*) MAXITO|\\ 1494Maximum number of iterations in the optimal orbital 1495algorithm\index{optimal orbital trial vector} 1496\cite{tuhjahjajpjjcp84}. 1497Default is 5. 1498 1499\item{\Key{MAXMOM}}\\ 1500\verb|READ (LUCMD,*) MAXMOM|\\ 1501The maximum order of the Cauchy moments calculated. The default order is 6. 1502 1503\item{\Key{GRID}}\\ 1504\verb|READ (LUCMD,*) NGRID|\\ 1505Read in the number of grid points to use in the numerical integration of the Cauchy moments. Default is 10. 1506 1507\item{\Key{QUADMOM}} 1508Sets $A$ and $B$ to the quadrupole\index{quadrupole operator} operators. 1509 1510\item{\Key{QUADXX/XY/XZ/YY/YZ/ZZ}} 1511Sets $A$ and $B$ to the XX, XY, XZ, YY, YZ, or ZZ component of the 1512quadrupole\index{quadrupole operator} operator, respectively. 1513 1514\item{\Key{PRINT}} \\ 1515\verb|READ (LUCMD,*),IPRC6 |\\ 1516 The line following gives the print level for the calculation of Cauchy moments. 1517 1518\item{\Key{PROPRT}}\\ 1519\verb|READ '(A)', LABEL|\\ 1520Sets $A$ and $B$ to a given operator with label; LABEL. 1521(The calculation of the operator must be specified to the integral 1522module, see section \ref{ch:hermit}.) 1523This keyword may be repeated for different properties. 1524 1525\item{\Key{THCC6}}\\ 1526\verb|READ *, THCC6|\\ 1527Relative convergence threshold for all requested linear response functions. 1528Default is 1.0D-3; note that this number should be at least 10 times 1529bigger than the final gradient norm in the SCF/MCSCF 1530wave function optimization.< 1531\end{description} 1532 1533 1534\noindent{\bf Comments:} 1535 1536You must tell the integral module to calculate the necessary one-electron integrals. 1537For \Key{C8SPH}, \Key{C8ATM}, or \Key{C8LMO} you will need 1538 1539\begin{verbatim} 1540**INTEGRALS 1541.SPHMOM 1542 3 1543\end{verbatim} 1544 1545which calculate spherical moments for $L = 0, \ldots, 3$. 1546For the \Key{C6xxx} and the \Key{C10xxx} options 1547you will need $L = 0, 1$ and $L = 0, \ldots, 5$, respectively. 1548 1549\subsection{Damped response calculation: \Sec{ABSORP}} 1550\label{sec:absorprsp} 1551 1552Input for specification of a damped response 1553calculation. 1554\index{damped response}\index{response!damped}\\ 1555By default, the solver 1556with symmetrized trial vectors \cite{kauczor:2011} is used. 1557 1558\begin{description} 1559\item{\Key{ALPHA}} \\ 1560Calculate the linear polarizability. 1561 1562\item{\Key{MCD}} \\ 1563Calculate the magnetic circular dichroism (MCD) and the Magnetic Optical Rotation Dispersion. 1564 1565\item{\Key{NSCD}} \\ 1566Calculate the Nuclear Spin Circular Dichroism (NSCD) and the Nuclear Spin Optical Rotation~\cite{vaara2014}. 1567It requires specification of the \verb|.PSO| integrals in 1568the \verb|*INTEGRALS| input section. 1569Note that at present NSCD calculations only work {\bf{without symmetry}}. 1570See \verb|rsp_cpp_nscd| for an example of NSCD calculations. 1571 1572\item{\Key{BETA}}\\ 1573Calculate the first-order hyperpolarizability. 1574 1575\item{\Key{SHG}}\\ 1576Only response functions connected with second harmonic 1577generation\index{second harmonic generation}\index{response!second harmonic generation}\index{quadratic response!second harmonic generation} 1578are computed, $\beta(-2\omega,\omega,\omega)$ . 1579 1580\item{\Key{FREQUE}} \\ 1581\verb|READ (LUCMD,*),ABS_NFREQ_ALPHA |\\ 1582\verb|READ (LUCMD,*) (ABS_FREQ_ALPHA(I), I = 1, ABS_NFREQ_ALPHA) | \\ 1583Select frequencies for which linear polarizability will be calculated. 1584The first line contains number of frequencies and in the second line the 1585frequencies of interest are specified. 1586 1587\item{\Key{FREQ I}} \\ 1588\verb|READ (LUCMD,*),FREQ1 FREQ2 STEP |\\ 1589Select the frequency interval for which linear polarizability will be calculated. 1590\verb|FREQ1| and \verb|FREQ2| refer to the first and the last frequency of 1591the interval, and \verb|STEP| is a step between frequencies of interest. 1592 1593\item{\Key{BFREQ}} \\ 1594\verb|READ (LUCMD,*),ABS_NFREQ_BETA_B |\\ 1595\verb|READ (LUCMD,*) (ABS_FREQ_BETA_B(I), I = 1, ABS_NFREQ_BETA_B) | \\ 1596The frequencies\index{frequency!cubic response} 1597$\omega_b$. Input as in \Key{FREQUE}. 1598Default only zero frequency (static). 1599 1600\item{\Key{BFREQI}} \\ 1601\verb|READ (LUCMD,*),FREQ1 FREQ2 STEP |\\ 1602Select the frequency interval for $\omega_b$. 1603\verb|FREQ1| and \verb|FREQ2| refer to the first and the last frequency in 1604the interval, and \verb|STEP| is a step between frequencies of interest. 1605 1606\item{\Key{CFREQ}} \\ 1607\verb|READ (LUCMD,*),ABS_NFREQ_BETA_C |\\ 1608\verb|READ (LUCMD,*) (ABS_FREQ_BETA_C(I), I = 1, ABS_NFREQ_BETA_C) | \\ 1609The frequencies\index{frequency!cubic response} 1610$\omega_c$. Input as in \Key{FREQUE}. 1611Default only zero frequency (static). 1612 1613\item{\Key{DAMPING}} \\ 1614\verb|READ (LUCMD,*),ABS_DAMP |\\ 1615 Select the broadening (damping) parameter $\gamma$. 1616 1617\item{\Key{MAXIT}} \\ 1618\verb|READ (LUCMD,*),ABS_MAXITER |\\ 1619 The maximum number of iterations. (Default 1620= 150 ) 1621 1622\item{\Key{MAXRM}} \\ 1623\verb|READ (LUCMD,*),ABS_MAXRM |\\ 1624 The maximum dimension of the reduced space. 1625(Default = 200) The damped response equations are solved in 1626a reduced space, which is increased 1627in each iteration. MAXRM should be increased, if equations for many 1628frequencies are to be solved. Sharp convergence thresholds also require 1629more iterations and thus larger dimension of the reduced space. 1630 1631\item{\Key{THCLR}} \\ 1632\verb|READ (LUCMD,*),ABS_THCLR|\\ 1633 The threshold for convergence (Default = 1.0D-3) 1634 1635\item{\Key{PRINT}} \\ 1636\verb|READ (LUCMD,*),IPRABSLRS |\\ 1637 The print level for the ABSLRS routines. 1638 1639\item{\Key{XX/YY/ZZCOMP}} \\ 1640 Only XX, YY or ZZ component of linear polarizability is calculated. 1641 1642\item{\Key{IMAG F}} \\ 1643 Select calculations for $i\omega$, {\it i.e.} when C$_6$ dispersion 1644coefficients are determined, linear polarizability $\alpha(i\omega)$ is 1645calculated. When \verb|.IMAG F| is specified, \verb|.FREQUE| and \verb|.FREQ I| 1646refer to imaginary frequencies, and the damping 1647parameter $\gamma = 0$. 1648 1649\item{\Key{ANALYZ}} \\ 1650 Analyze the composition of the wave function. 1651 1652\item{\Key{NBATCH}} \\ 1653\verb|READ (LUCMD,*),ABS_NBATCHMAX|\\ 1654 The number of linear transformations performed in one batch. Used in 1655calculations for many frequencies on large systems. 1656If calculations are performed using DFT, it is recommended to use 1657a multiplicity of 4 to obtain full efficiency. 1658 1659\item{\Key{OLDCPP}}\\ 1660 The old complex polarization propagator 1661solver \cite{pndmbhjajjojcp123,pndmbhjajjojcp115} is used 1662in the damped response calculations. For {\Key{MCSCF}} calculations, the 1663old CPP solver is always used. 1664\item{\Key{EXCITA}}\\ 1665\verb|READ (LUCMD,*),NEXCITED_STATES|\\ 1666 Number of first eigenvectors used as the trial vectors in the CPP solver. 1667It is neglected in the input unless the 1668{\Key{OLDCPP}} is specified. 1669 1670\end{description} 1671\subsection{Electron Spin Resonance: \Sec{ESR}} 1672 1673Calculation of ESR parameters\index{ESR} 1674 1675\subsubsection{Hyperfine coupling} 1676 1677Default\index{hyperfine coupling}: hyperfine coupling tensors using 1678the Restricted-Unrestricted Approach\index{restricted-unrestricted method}. 1679 1680\begin{description} 1681\item{\Key{FCCALC}} \\ 1682Calculate the isotropic Fermi-contact contributions to hyperfine coupling tensors 1683 1684\item{\Key{SDCALC}} \\ 1685Calculate the spin-dipole contributions to the hyperfine coupling tensor 1686 1687\item{\Key{ATOMS}} \\ 1688\verb|READ (LUCMD,*),ESRNUC |\\ 1689\verb|READ (LUCMD,*) (NUCINF(IG), IG = 1, ESRNUC) | \\ 1690Select atoms for which to calculate hyperfine coupling constants. 1691The first line contains the number of atoms and the second line the 1692index of each atom (ordered as in the molecule input file \molinp) 1693 1694\item{\Key{MAX IT}} \\ 1695\verb|READ (LUCMD,*),MAXESR |\\ 1696 The line following gives the maximum number of iterations. (Default = 60) 1697 1698\item{\Key{PRINT}} \\ 1699\verb|READ (LUCMD,*),IPRESR |\\ 1700 The line following gives the print level for the ESR routines. 1701 1702\item{\Key{THCESR}} \\ 1703\verb|READ (LUCMD,*),THCESR|\\ 1704 The line following is the threshold for convergence (Default = 1.0D-5) 1705 1706\end{description} 1707The following options are obsolete but are kept for backward compatibility. 1708They are replaced by \Key{FCCALC} and \Key{SDCALC} above which also 1709enables the printing of the tensors of the most important isotopes of the 1710atoms in commonly used units. 1711\begin{description} 1712 1713\item{\Key{SNGPRP}} \\ 1714\verb|READ (LUCMD,'(A)'), LABEL|\\ 1715 Singlet Operator. The line following is the label in the AOPROPER file. 1716 1717\item{\Key{TRPPRP}} \\ 1718\verb|READ (LUCMD,'(A)'), LABEL |\\ 1719 Triplet Operator. The line following is the label in the AOPROPER file. 1720 1721 1722\end{description} 1723 1724\subsubsection{Zero-field splitting: \Key{ZFS}} 1725 1726Calculation of the the electronic spin--spin contribution to the zero-field splitting 1727tensor: 1728 1729\begin{description} 1730 \item{\Key{ZFS}} \\ 1731\end{description} 1732 1733\subsubsection{Electronic g-tensors: \Key{G-TENSOR}} 1734\label{sec:g-tensor} 1735Calculation of the electronic g-tensor: 1736 1737\begin{description} 1738 \item{\Key{G-TENSOR}} \\ 1739 Initializes input block for g-tensor related options 1740\end{description} 1741The default is to calculate all contributions. The following 1742options selects individual contributions 1743\begin{description} 1744 \item{\Key{RMC}} 1745 Relativistic mass correction 1746 \item{\Key{OZSO1}} 1747 Second-order (paramagnetic) orbital-Zeeman + 1-electron spin-orbit contributions 1748 \item{\Key{OZSO2}} 1749 Second-order (paramagnetic) orbital-Zeeman + 2-electron spin-orbit contributions 1750 \item{\Key{GC1}} 1751 1-electron gauge correction (diamagnetic) contributions 1752 \item{\Key{GC2}} 1753 2-electron gauge correction (diamagnetic) contributions 1754 \item{\Key{ECC}} 1755 Choose electron center of charge (ECC) as gauge origin. 1756\end{description} 1757The following are utility options for modifying the default calculational 1758procedure. 1759\begin{description} 1760 \item{\Key{ADD-SO}} 1761 Adds the 1- and 2-electron spin-orbit operators. This 1762 option may be used when one is not interested in the individual 1763 1- and 2-electron contribution to the paramagnetic g-tensor, 1764 since it reduces the number of response equations to be solved. 1765 \item{\Key{MEAN-FIELD}} 1766 Uses the approximate atomic mean field (AMFI) spin-orbit operator 1767 for evaluating the paramagnetic contributions. 1768% \item{\Key{OWN-OT}} Calculates separately the spin-own-orbit and 1769% spin-other-orbit contributions to the 2-electron spin-orbit 1770% operator contribution to the g tensor. 1771 \item{\Key{SCALED}} 1772 Uses the approximate 1-electron spin-orbit operator with scaled nuclear 1773 charges taken from Ref.~\cite{skmwsmsgjpca102} for evaluating the paramagnetic contributions. 1774%\item{\Key{TEST A}} 1775 \item{\Key{ZERO}} 1776 \verb|READ(LUCMD,'(A80)')G_LINE |\\ 1777 This option is mainly for linear molecules in a $\Sigma$ state. 1778 Specifying e.g. "ZZ" on the input line instructs the program 1779 to skip the calculation of the paramagnetic contribution to $g_{zz}$. 1780\end{description} 1781 1782\subsection{Hyperfine Coupling Constants: \Sec{HFC}} 1783 1784Calculation of hyperfine coupling constants using restricted-unrestricted Kohn-Sham method\index{HFC} 1785 1786\begin{description} 1787\item{\Key{HFC-FC}} \\ 1788Calculate the isotropic Fermi-contact contributions to hyperfine coupling tensors of all nuclei in 1789molecule with nonzero nuclear spin. 1790 1791\item{\Key{HFC-SD}} \\ 1792Calculate the spin-dipole contributions to the hyperfine coupling tensor of all nuclei in molecule 1793with nonzero nuclear spin. 1794 1795\item{\Key{HFC-SO}} \\ 1796Calculate the spin-orbit contributions to the hyperfine coupling tensor of all nuclei in molecule 1797with nonzero nuclear spin. By default mean field approximation is used for spin-orbit interaction. 1798 1799\item{\Key{BRT-SO}} \\ 1800Requests usage of two-electron spin-orbit interaction integrals in computation of spin-orbit contribution 1801to hyperfine coupling tensor. This keyword must be combined with \Key{SPIN-ORBIT} in the \Sec{*INTEGRALS} input module. 1802 1803\item{\Key{EFF-SO}} \\ 1804Requests usage of effective scaled charge spin-orbit interaction integrals in computation of spin-orbit contribution 1805to hyperfine coupling tensor. 1806 1807\item{\Key{PRINT}} \\ 1808\verb|READ (LUCMD,*),IPRESR |\\ 1809 The line following gives the print level for the HFC routines. 1810 1811\end{description} 1812