Hybrid approach to relativistic Gaussian basis functions: Theory and applications

Abstract

We present a hybrid method to solve the relativistic Hartree-Fock-Roothan equations where the one- and two-electron radial integrals are evaluated numerically by defining the basis functions on a grid. This procedure reduces the computational costs in the evaluation of two-electron radial integrals. The orbitals generated by this method are employed to compute the ionization potentials, excitation energies, and oscillator strengths of alkali-metal atoms and elements of group IIIA through second-order many-body perturbation theory. The computed properties are in excellent agreement with the experiment and other correlated theories