Computer Physics Communications Program LibraryPrograms in Physics & Physical Chemistry |

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Manuscript Title: Diagrammatic many-body perturbation expansion for atoms and
molecules: I. General organization. | ||

Authors: D.M. Silver | ||

Program title: MBPT ORGANIZATION | ||

Catalogue identifier: ACXF_v1_0Distribution format: gz | ||

Journal reference: Comput. Phys. Commun. 14(1978)71 | ||

Programming language: Fortran. | ||

Computer: IBM 360/91. | ||

Operating system: ASP. | ||

Program overlaid: yes | ||

RAM: 200K words | ||

Word size: 8 | ||

Peripherals: disc. | ||

Keywords: Structure, Diagram, Many-body, Atomic physics, Molecular physics, Electronic, Perturbation theory, Pade approximant, Quantum chemistry. | ||

Classification: 2.1, 16.1. | ||

Subprograms used: | ||

Cat
Id | Title | Reference |

ACXG_v1_0 | MBPT LADDER DIAGRAMS | CPC 14(1978)81 |

ACXH_v1_0 | MBPT RING DIAGRAMS | CPC 14(1978)91 |

Nature of problem:The determination of perturbative solutions to the non-relativistic Schrodinger equation for the electronic structure of atomic and molecular systems is considered within the Born-Oppenheimer approximation. | ||

Solution method:The diagrammatic many-body perturbation expansion is employed through third-order in the energy and first-order in the wavefunction, including all many-body effects that arise. The calculations are performed within algebraic approximation in which eigenfunctions are parameterized by expansion in a finite set of basis functions. Computer algorithms are presented for the organization and sorting of the one- electron and two-electron interaction integrals; and the calculation of final results, including Pade approximants and variational many-body perturbative upper-bounds to the energy eigenvalue. | ||

Restrictions:These programs are restricted to non-degenerate, closed-shell ground- states of atoms and molecules. The reference wavefunction must be closed-shell matrix Hartree-Fock single-determinantal wavefunction. Program dimension statements limit the basis set size to 10 occupied spatial orbitals (20 virtual electrons) and 25 unoccupied spatial orbitals (50 virtual states): these dimensions can easily be increased if necessary. | ||

Unusual features:This program is an integral part of a set of programs. This program prepares the input to the other parts of the set and uses the output from those routines to calculate the final results. | ||

Running time:Running times depend strongly on the basis set size and on the number of occupied orbitals: some timing data have been presented. The test run requires approx. 1.5 s of CPU time on the IBM 360/91 for the subprograms within the domain of this paper. |

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