ISSN:
0020-7608
Keywords:
Computational Chemistry and Molecular Modeling
;
Atomic, Molecular and Optical Physics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
In carrying out our plan for doing multicenter molecular integrals over Slater-type orbitals, it is necessary to evaluate the Löwdin α-function over a grid from the origin of the coordinate system to the displacement distance of the center of the orbital. A previous article obtained excellent results by expanding the exponentials in the α-function, for both interior and exterior regions. However, if the displacement distance multiplied by the screening constant, i.e., the ζa parameter, is larger than 16, we suggest that it may be more efficient in time and storage if we use the closed formula for the α-function for values of the radial distance r greater than 8. This remarkable rule of thumb was tested for a variety of orbitals up to ζa=64 and one to ζa=128. Also, in the exterior region, the formula may always be used if ζa≥16. This strategy necessitates using the formula in quadruple precision arithmetic. © 1996 John Wiley & Sons, Inc.
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
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