1% 2% $Id$ 3% 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. 145 146 147