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[Licence| Download | New Version Template] aefr_v1_0.tar.gz(165 Kbytes)
Manuscript Title: Multiconfiguration electron density function for the ATSP2K-package
Authors: A. Borgoo, O. Scharf, G. Gaigalas, M. Godefroid
Program title: DENSITY
Catalogue identifier: AEFR_v1_0
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 181(2010)426
Programming language: FORTRAN 90.
Computer: HP XC Cluster Platform 4000.
Operating system: HP XC System Software 3.2.1, which is a Linux distribution compatible with Red Hat Enterprise Advanced Server.
Word size: 32 bits
Keywords: Electron density, Density matrix, Natural orbitals, Multiconfiguration wave functions.
PACS: 31.15.-p, 31.15.ae, 31.15.V-, 31.15.xh, 45.10.Na.
Classification: 2.1, 2.9, 4.1.

Subprograms used:
Cat Id Title Reference
ADLY_v2_0 ATSP2K CPC 176(2007)559

Nature of problem:
This program determines the atomic electronic density in the MCHF (LS ) or Breit-Pauli (LS J) approximation. It also evaluates the natural orbitals by diagonalizing the density matrix.

Solution method:
Building the density operator using second quantization - Spherical symmetry averaging - evaluating the matrix elements of the one-body excitation operators in the configuration state function (CSF) space using the angular momentum theory in orbital, spin, and quasispin spaces.

Original restrictions from ATSP2K package, i.e. all orbitals within a wave function expansion are assumed to be orthonormal. Configuration states are restricted to at most eight subshells in addition to the closed shells common to all configuration states. The maximum size of the working arrays, related to the number of CSFs and active orbitals, is limited by the available memory and disk space.

Unusual features:
The programming style is essentially F77 with extensions for the POINTER data type and associated memory allocation. These have been available on workstations for more than a decade, but their implementations are compiler dependent. The present code has been installed and tested extensively using the Portland Group, pgf90, compiler.

Running time:
The calculation of the electron density for a n = 9 complete active space (CAS) MCHF wave function (271 733 CSFs - 45 orbitals) takes around 9 minutes on one AMD Opteron dual-core @ 2.4 GHz CPU.

[1] "An MCHF atomic-structure package for large-scale calculation", Charlotte Froese Fischer, Georgio Tachiev, Gediminas Gaigalas and Michel R. Godefroid, Computer Physics Communications 176 (2007) 559-579