This manual explains how to use the PSI3 suite of ab initio quantum chemical programs. In this section, we provide an overview of some of the features of PSI3 along with the prerequisite steps for running calculations. Section 2 provides a brief tutorial to help new users get started. Section 3 offers further details into the structure of PSI3 input files and a discussion of some of the most important options. Later sections deal with the different types of computations which can be done using PSI3 (e.g., Hartree-Fock, MP2, coupled-cluster) and general procedures such as geometry optimization and vibrational frequency analysis. The appendix will eventually include a description of the input keywords and command-line options for each module, as well as numerous examples of PSI3 input and basis set files. For the latest PSI3 documentation, check www.psicode.org.
The PSI3 package was developed to perform high-accuracy quantum mechanical computations on challenging chemical species and to provide an infrastructure for the development of new theoretical techniques. Hence, it has a very flexible input scheme which allows non-standard computations, and it is easily adapted to enable new capabilities.
The following citation should be used in any publication utilizing the PSI3 program package:
T. Daniel Crawford, C. David Sherrill, Edward F. Valeev, Justin T. Fermann, Rollin A. King, Matthew L. Leininger, Shawn T. Brown, Curtis L. Janssen, Edward T. Seidl, Joseph P. Kenny, and Wesley D. Allen, J. Comput. Chem. 28, 1610-1616 (2007).