title: PSI3: an open-source Ab Initio electronic structure package.
abstract: PSI3 is a program system and development platform for ab initio molecular electronic structure computations. The package includes mature programming interfaces for parsing user input, accessing commonly used data such as basis-set information or molecular orbital coefficients, and retrieving and storing binary data (with no software limitations on file sizes or file-system-sizes), especially multi-index quantities such as electron repulsion integrals. This platform is useful for the rapid implementation of both standard quantum chemical methods, as well as the development of new models. Features that have already been implemented include Hartree-Fock, multiconfigurational self-consistent-field, second-order Møller-Plesset perturbation theory, coupled cluster, and configuration interaction wave functions. Distinctive capabilities include the ability to employ Gaussian basis functions with arbitrary angular momentum levels; linear R12 second-order perturbation theory; coupled cluster frequency-dependent response properties, including dipole polarizabilities and optical rotation; and diagonal Born-Oppenheimer corrections with correlated wave functions. This article describes the programming infrastructure and main features of the package. PSI3 is available free of charge through the open-source, GNU General Public License.
authors.affiliation: Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061.
authors.forename: T Daniel
authors.initials: TD
authors.lastname: Crawford
authors.affiliation: Center for Computational Molecular Science and Technology, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332.
authors.forename: C David
authors.initials: CD
authors.lastname: Sherrill
authors.affiliation: Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061.
authors.forename: Edward F
authors.initials: EF
authors.lastname: Valeev
authors.affiliation: Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01002.
authors.forename: Justin T
authors.initials: JT
authors.lastname: Fermann
authors.affiliation: Department of Chemistry, Bethel University, St. Paul, Minnesota 55112.
authors.forename: Rollin A
authors.initials: RA
authors.lastname: King
authors.affiliation: Sandia National Laboratories, Livermore, California 94551.
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Leininger
authors.affiliation: Pittsburgh Supercomputing Center, Pittsburgh, Pennsylvania 15213.
authors.forename: Shawn T
authors.initials: ST
authors.lastname: Brown
authors.affiliation: Sandia National Laboratories, Livermore, California 94551.
authors.forename: Curtis L
authors.initials: CL
authors.lastname: Janssen
authors.affiliation: Lawrence Livermore National Laboratories, Livermore, California 94550.
authors.forename: Edward T
authors.initials: ET
authors.lastname: Seidl
authors.affiliation: Sandia National Laboratories, Livermore, California 94551.
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Kenny
authors.affiliation: Center for Computational Chemistry and Department of Chemistry, University of Georgia, Athens, Georgia 30602.
authors.forename: Wesley D
authors.initials: WD
authors.lastname: Allen