The use of gaussian nuclear charge distributions for the calculation of relativistic electronic wavefunctions using basis set expansions

Abstract

It is demonstrated that the use of a Gaussian charge distribution to represent the nucleus is advantageous in relativistic quantum chemical basis set expansion calculations. It removes the singularity at the origin of the Dirac wavefunction, leading to a more rapid convergence of the ground-state energy expectation value as a function of basis set size and to a large reduction in the exponents of the optimized basis sets. Hence, smaller basis sets can be used for HFD calculations.