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436. G70DATA and LAOIM
by A. Chung-Phillips, K. H. Aufderheide and C. J.
Eyermann, Department of Chemistry, Miami University,
Oxford, Ohio 45056
This package consists of two separate programs which
are intended to work with GAUSSIAN 70 (QCPE 236). You
must have a copy of the program to make use of this
package.
G70DATA--This program is to be used with an IBM version
of GAUSSIAN 70 (QCPE 236). It retrieves from GAUSSIAN
70 certain AO and MO quantities and writes the nonzero
values onto an appropriate output device. For an AO
integral, the nonzero value must further correspond to
a unique AO index symmetry. The quantities are: (1)
one-electron AO integrals, including the overlap (S),
core (T + V), and dipole moment (X, Y and Z); (2) two-
electron AO integrals representing electron repulsion;
and (3) the final SCF-MO energies and coefficients
(including those for virtual orbitals) and density
matrix.These data are useful for calculating
molecular properties beyond those produced by GAUSSIAN
70 and for carrying out configuration interaction and
perturbation treatments. Specifically, the program is
designed to create input data for the calculation of
localized atomic orbitals and related properties.
Sample JCL statements and input-output details are
extensively documented in the COMMENT statements within
the program. Input examples for STO-3G calculations
are given for the HF, HCl, C2H2 , and CH3 molecules
which, respectively, require 0.5, 0.7, 1.2, and 0.8
minutes total to run GAUSSIAN 70 and G70DATA on an IBM
370/148, with 171, 587, 1448, and 630 output records
from G70DATA.
LAOIM--This program derives LAOs and related
properties1 based on a given ab initio SCF-MO
wavefunction expanded from a minimal AO basis set. It
calculates LAOs and their populations from the SCF
density matrix, AO overlap integrals, and AO electron
repulsion integrals. It also determines the mean
position of an electron in the LAO and the angle
between each pair of valence LAOs from the AO moment
(X, Y and Z) integrals. In addition to treating a
closed-shell molecule with all AOs included, the
program provides options for open shells and frozen
atomic cores. The case for open shell has not been
tested extensively. The use of frozen atomic cores for
heavy atoms is found highly practical with respect to
computer time.
This program is set up to use the output from G70DATA
but may be modified to accept similar inputs. As in
GAUSSIAN 70, heavy atoms with atomic numbers from 2 to
18 are allowed, but calculations are restricted to STO-
3G for use here. To save core storage, the programming
feature of dynamic data storage2 is incorporated. The
limiting factor for the core array storage is ITOTAL,
ITOTAL=IC+13*NATOM+12*N+22*N**24-byte words,
where IC=1090 or 8694 words (depending on the largest
heavy atom having 5 or 9 AOs), NATOM = number of atoms,
and N = number of AOs. For a large molecule with low
symmetry, the number of non-zero AO electron-repulsion
integrals may become the limiting factor; this problem
may be resolved by more efficient programming.
Documentation of the program appears as COMMENT
statements in the source program. Sample input is for
the HF molecule which requires: 1980 words for core
array storage; 131 input records; and 19.9 minutes to
run on an IBM 370/148 with all AOs included. Using
frozen atomic cores for the HF, HCl, C2H2, and CH3
molecules, the respective running times are 3.4, 3.8,
5.8, and 1.2 minutes.
___________
References:
1 K. H. Aufderheide, J. Chem. Phys., 73, 1777 (1980);
K. H. Aufderheide and A. Chung-Phillips, ibid., 73,
1789 (1980).
2 A. Chung-Phillips and R. W. Rosen, Computer Journal,
18, 342 (1975).
FORTRAN IV (IBM 360/370)
Lines of Code: 2425
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