The PSI3 suite of quantum chemical programs is designed for efficient, high-accuracy calculations of properties of small to medium-sized molecules. The package's current capabilities include a variety of Hartree-Fock, coupled cluster, complete-active-space self-consistent-field, and multi-reference configuration interaction models. Molecular point-group symmetry is utilized throughout to maximize efficiency. The latest version of the code, PSI 3.3, rests upon a completely rewritten infrastructure relative to previous versions of the package. Non-standard computations are possible using a customizable input format. Package highlights include:
  • Arbitrarily high angular momentum levels in integrals and derivative integrals. (Up to m-type functions have been tested.)
  • Coupled cluster methods including CC2, CCSD, CCSD(T), and CC3 with RHF, ROHF, UHF, and Brueckner orbitals.
  • Determinant-based CI including CASSCF, RAS-CI, and Full CI.
  • Multithreaded integral-direct SCF, MP2, and MP2-R12.
  • Excited state methods: CIS, CIS(D), RPA, EOM-CCSD, and CC3.
  • Analytic energy gradients for CCSD with RHF, ROHF, and UHF orbitals.
  • Coupled cluster linear response methods for static and dynamic polarizabilities and optical rotation.
  • Diagonal Born-Oppenheimer correction (DBOC) for RHF, ROHF, UHF, and CI wave functions.
The latest version of the PSI3 package is psi-3.3.0 ("Hannah"), which was released on 11 April 2007.
Primary development on PSI3 has been carried out by:
T. Daniel Crawford (Virginia Tech) C. David Sherrill (Georgia Tech)
Edward F. Valeev (Virginia Tech) Rollin A. King (Bethel University)

The development of PSI3 has been supported in part by the U.S. National Science Foundation under CAREER Awards CHE-0133174 (TDC), CHE-0094088 (CDS) and the U.S. Department of Energy under lab-directed research and development grants from Sandia National Laboratories and Oak Ridge National Laboratory.
If you have comments, questions, or suggestions, email the developers at psicode@users.sourceforge.net.

This page was last updated on 06 August 2007.