Gaussian-Type Functions for Polyatomic Systems. I

TLDR

Rapid advances in computer power make it desirable to evaluate the usefulness of Gaussian‑type orbitals for large‑scale molecular calculations. This paper investigates the suitability of Gaussian‑type orbitals at the atomic Hartree–Fock level. Discussions on this issue are presented in the latter part of the paper. Gaussian‑type basis functions require more than twice the terms needed for Slater‑type functions in Hartree–Fock calculations, yet this does not mandate a definitive preference for Slater‑type orbitals.

Abstract

In view of rapid progress of computer capability, it is very desirable to have a reliable assessment of the usefulness of Gaussian-type orbitals as basis functions for large-scale molecular calculations. In the present paper several attempts are made to answer this question mainly at the level of atomic Hartree—Fock calculations. The necessary number of terms of Gaussian-type basis functions in the analytical Hartree—Fock expansion calculation is apparently more than twice as much as the number of terms needed in the expansion with Slater-type basis functions. However, this fact does not necessarily suggest a definite choice of Slater-type orbitals. Discussions pertinent to this point are presented in the latter part of the present paper.