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237. GAUSFIT: Gaussian Fit to Slater Orbitals
by Richard E. Stanton and Michael Herman, Department of Chemistry, Canisius College, Buffalo, New York 14208 This program provides a fast, optimum Gaussian fit to the radial factor of a single Slater-type orbital (STO) or an arbitrary linear combination of as many as ten STOs at fixed angular momentum. It is applicable to s, p or d orbitals. The optimum fit is defined by a minimization of a variance criterion that does not include normalization constraints. The user has the option of varying both the linear and exponential coefficients of the Gaussian-type orbitals (GTOs) in the fitting function or of varying the linear coefficients alone. The quality of the Gaussian fit can be judged partially from the magnitude of the variance. The program includes two additional quality tests on an optional basis. The first is a point comparison of the Slater function and its Gaussian fit; the second compares the values of two-center integrals (angular momentum effects included) for the two functions at a series of internuclear distances. The comparisons can be carried out at radii and internuclear distances specified by the user or at the default distances: 0.0, 0.1, 0.2,..., 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0 Bohrs. FORTRAN IV Lines of Code: 914 Recommended Citation: R. E. Stanton and M. Herman, QCPE 11, 237 (1973). |