Implementation of atomic basis set composed of 1s Gaussian and 1s Slater-type orbitals to carry out quantum mechanics molecular calculations

Abstract

A mixed atomic basis set formed with ls Slater‐type orbitals and 1s floating spherical Gaussian orbitals is implemented. Evaluation of multicenter integrals is carried out using a method based on expansion of binary products of atomic basis functions in terms of a complete basis set, and a systematic analysis is performed. The proposed algorithm is very stable and furnishes fairly good results for total energy and geometry. An LCAO‐SCF test calculation is carried out on LiH. The trends observed show that there are some combinations of mixed orbitals that are appropriate to describe the system. ©1999 John Wiley & Sons, Inc. J Comput Chem 20: 604–609, 1999

A new algorithm to evaluate bielectronic integrals with 1s Slater‐type orbitals obtained by the integral transforms

“…The inclusion of Slater‐type orbitals (STO) in molecular calculations is a well‐defined problem in quantum chemistry (see 1 and references therein). A problem in molecular physics, where 1 s STO appear, is in the applications of the mixed atomic basis set 2. The present work introduces a variation of the integral transform method (ITM) 3, 4 to evaluate the general four‐center bielectronic integrals involving 1 s STO, which is simpler than the one associated to the ITM.…”