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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 |