A basis set composed of only 1s slater orbitals and 1s Gaussian orbitals to perform molecular calculations, SCF-LCAO approach

Abstract

This work introduces molecular basis sets considering only 1s Slater orbitals and 1s Gaussian orbitals. The main purpose is the construction of a stable atomic model, to be useful for carrying out molecular calculations; among many possibilities, a tetrahedral structure is proposed. With these tetrahedral structures, together with a few floating 1s Gaussian orbitals, a molecular geometry optmization is performed. Test calculations, at the level of SCF-LCAO, for the molecules of OH2 and SH2, are presented; they show the proper trend, i.e., very different optimized geometrical parameters.