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2% $Id$
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4\label{sec:intro}
5
6NWChem is a computational chemistry package designed to run on
7high-performance parallel supercomputers.
8Code capabilities include the calculation of molecular electronic
9energies and analytic gradients using Hartree-Fock self-consistent field (SCF) theory, Gaussian
10density function theory (DFT), and second-order perturbation theory.
11For all methods, geometry optimization is available to determine energy minima and transition states.
12Classical molecular dynamics capabilities
13provide for the simulation of macromolecules and solutions, including
14the computation of free energies using a variety of force fields.
15
16NWChem is scalable, both in its ability to treat large problems
17efficiently, and in its utilization of available parallel computing
18resources.  The code uses the parallel programming tools TCGMSG and
19the Global Array (GA) library developed at PNNL for the High Performance
20Computing and Communication (HPCC) grand-challenge
21software program and the Environmental Molecular Sciences Laboratory
22(EMSL) Project.  NWChem has been optimized to perform calculations on
23large molecules using large parallel computers, and it is unique in
24this regard.
25
26This document is intended as an aid to chemists using the code for
27their own applications.  Users are not expected to have a detailed
28understanding of the code internals, but some familiarity with the
29overall structure of the code, how it handles information, and the
30nature of the algorithms it contains will generally be helpful.  The
31following sections describe the structure of the input file, and give
32a brief overview of the code architecture.  All input directives
33recognized by the code are described in detail, with options,
34defaults, and recommended usages, where applicable.  The appendices
35present additional information on the molecular geometry and basis
36function libraries included in the code.
37
38\section{Citation}
39
40The EMSL Software Agreement stipulates that the use of NWChem will be
41acknowledged in any publications which use results obtained with
42NWChem.  The acknowledgment should be of the form:
43\begin{quote}
44
45  NWChem Version \nwchemversion, as developed and distributed by
46  Pacific Northwest National Laboratory, P.~O.~Box 999, Richland,
47  Washington 99352 USA, and funded by the U.~S.~Department of Energy,
48  was used to obtain some of these results.
49\end{quote}
50
51The words ``A modified version of'' should be added at the beginning,
52if appropriate.  {\em Note: Your EMSL Software Agreement contains the
53complete specification of the required acknowledgment.}
54
55Please use the following citation when publishing results obtained
56with NWChem:
57\begin{quote}
58Straatsma, T.P.; Apr\`a, E.; Windus, T.L.; Bylaska, E.J.; de Jong, W.;
59Hirata, S.; Valiev, M.; Hackler, M.; Pollack, L.; Harrison, R.;
60Dupuis, M.; Smith, D.M.A; Nieplocha, J.; Tipparaju V.; Krishnan, M.;
61Auer, A.A.; Brown, E.; Cisneros, G.; Fann, G.; Fr\"uchtl, H.; Garza, J.;
62Hirao, K.; Kendall, R.; Nichols, J.; Tsemekhman, K.; Wolinski, K.;
63Anchell, J.; Bernholdt, D.; Borowski, P.; Clark, T.; Clerc, D.;
64Dachsel, H.; Deegan, M.; Dyall, K.; Elwood, D.; Glendening, E.;
65Gutowski, M.; Hess, A.; Jaffe, J.; Johnson, B.; Ju, J.; Kobayashi, R.;
66Kutteh, R.; Lin, Z.; Littlefield, R.; Long, X.; Meng, B.; Nakajima,
67T.; Niu, S.; Rosing, M.; Sandrone, G.; Stave, M.; Taylor, H.; Thomas,
68G.; van Lenthe, J.; Wong, A.; Zhang, Z.; {\em NWChem, A Computational
69Chemistry Package for Parallel Computers, Version 4.6} (2004),
70Pacific Northwest National Laboratory, Richland, Washington
7199352-0999, USA. \\
72{\em High Performance Computational Chemistry: an Overview of NWChem a
73Distributed Parallel Application}, Kendall, R.A.; Apr\`a, E.;
74Bernholdt, D.E.; Bylaska, E.J.; Dupuis, M.; Fann, G.I.; Harrison,
75R.J.;  Ju, J.; Nichols, J.A.; Nieplocha, J.; Straatsma, T.P.; Windus,
76T.L.; Wong, A.T. Computer Phys. Comm., 2000, {\bf 128}, 260--283 .
77\end{quote}
78
79If you use the DIRDYVTST portion of NWChem, please also use the additional
80citation:
81\begin{quote}
82  DIRDYVTST, Yao-Yuan Chuang and Donald G. Truhlar,
83  Department of Chemistry and Super Computer Institute,
84  University of Minnesota; Ricky A. Kendall,Scalable Computing Laboratory,
85  Ames Laboratory and Iowa State University; Bruce C. Garrett and Theresa L.
86  Windus, Environmental Molecular Sciences Laboratory, Pacific Northwest
87  Laboratory.
88\end{quote}
89
90\section{User Feedback}
91
92This software comes without warranty or guarantee of support,
93but we do try to meet the needs of our user community.  Please send bug
94reports, requests for enhancement, or other comments to
95
96\begin{verbatim}
97 nwchem-users@emsl.pnl.gov
98\end{verbatim}
99
100When reporting problems, please provide as much information as possible,
101including:
102
103\begin{itemize}
104\item detailed description of problem
105\item site name %(e.g., EMSL, NERSC, \ldots)
106\item platform you are running on, including
107\begin{itemize}
108\item vendor name
109\item computer model
110\item operating system
111\item compiler
112\end{itemize}
113\item input file
114\item output file
115%\item contact name and telephone number
116\end{itemize}
117
118Users can also subscribe to the {\tt nwchem-users@emsl.pnl.gov}
119electronic mailing list itself.
120This is intended as a general forum through which code
121users can contact one another and the developers, to share experience
122with the code and discuss problems.  Announcements of new releases and
123bug fixes will also be made to this list.
124
125To subscribe to the user list, send a message to
126\begin{verbatim}
127  majordomo@emsl.pnl.gov
128\end{verbatim}
129The body of the message must contain the line
130\begin{verbatim}
131  subscribe nwchem-users
132\end{verbatim}
133
134The automated list manager is capable of recognizing a number of
135commands, including ; ``subscribe'', ``unsubscribe'', ``get'', ``index'',
136``which'', ``who'', ``info'' and ``lists''.  The command ``end'' halts
137processing of commands.  It will provide some help if the message
138includes the line {\tt help} in the body.
139
140%Messages can be posted to
141%the list by sending mail to {\tt nwchem-users@emsl.pnl.gov}.  Users
142%are encouraged to report problems to the support address rather than the mailing list,
143%since the support address (listed at the beginning of this section) interfaces to an automated
144%bug tracking mechanism.
145
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