Programs in Physics & Physical Chemistry
|[Licence| Download | New Version Template] acxf_v1_0.gz(20 Kbytes)|
|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_0|
Distribution 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|
|Keywords: Structure, Diagram, Many-body, Atomic physics, Molecular physics, Electronic, Perturbation theory, Pade approximant, Quantum chemistry.|
|Classification: 2.1, 16.1.|
|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.
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.
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.
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 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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