Computer Physics Communications Program LibraryPrograms in Physics & Physical Chemistry |

[Licence| Download | New Version Template] acxg_v1_0.gz(9 Kbytes) | ||
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Manuscript Title: Diagrammatic many-body perturbation expansion for atoms and
molecules: II. Second-order and third-order ladder energies. | ||

Authors: D.M. Silver | ||

Program title: MBPT LADDER DIAGRAMS | ||

Catalogue identifier: ACXG_v1_0Distribution format: gz | ||

Journal reference: Comput. Phys. Commun. 14(1978)81 | ||

Programming language: Fortran. | ||

Computer: IBM 360/91. | ||

Operating system: ASP. | ||

Program overlaid: yes | ||

RAM: 200K words | ||

Word size: 8 | ||

Peripherals: disc. | ||

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

Classification: 2.1, 16.1. | ||

Subprograms used: | ||

Cat
Id | Title | Reference |

ACXF_v1_0 | MBPT ORGANIZATION | CPC 14(1978)71 |

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 the algebraic approximation in which eigenfunctions are parameterized by expansion in a finite set of basis functions. Computer algorithms are presented for the evaluation of second-order energies; overlap integrals over the first-order perturbative wavefunction; and third-order particle-particle and hole-hole ladder diagrams. | ||

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

Unusual features:This program is an integral part of a set of programs, (Comp. Phys. Commun. 14(1978)71, 14(1978)91). This program requires input from a previous part of the set and returns its output to those routines. | ||

Running time:Running time depend strongly on the basis set size and on the number of occupied orbitals: some timing data have been presented. The test run requires ~0.6 s of CPU time on the IBM 360/91 for the subprogram within the domain of this paper. |

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