Elsevier Science Home
Computer Physics Communications Program Library
Full text online from Science Direct
Programs in Physics & Physical Chemistry
CPC Home

[Licence| Download | New Version Template] aduw_v1_0.tar.gz(31 Kbytes)
Manuscript Title: Four-index integral transformation exploiting symmetry
Authors: Shigeyoshi Yamamoto, Umpei Nagashima
Program title: SYM4TR
Catalogue identifier: ADUW_v1_0
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 166(2005)58
Programming language: Fortran 95.
Computer: IBM, HP Alpha server, PC.
Operating system: AIX, TRU64, Linux.
Keywords: four-index integral transformation, symmetry adaptation, sparsity, point group, electron repulsion integral, two-electron integral.
PACS: 31.15.Ar.
Classification: 16.10.

Nature of problem:
Molecular orbital calculations including electron correlation effects usually require electron repulsion integrals to be transformed from an atomic orbital (AO) basis to a molecular orbital (MO) basis. By exploiting the sparsity of molecular integrals, the computational cost and memory needed for the transformation are minimized.

Solution method:
The sparsity of molecular integrals is exploited. The program treats only nonzero integrals. The length of running indices in DO loops is reduced using the block-diagonal form of the MO coefficient matrix. In the present program, the point group is limited to D2h and its subgroups.