Computational strategies for a four-component Dirac-Kohn-Sham program: Implementation and first applications

Abstract

An implementation of the generalized gradient approximation within the four-component formulation of relativistic density-functional theory using G -spinor basis sets is presented. This approach is based on the direct evaluation of the relativistic density and its gradient from the G -spinor amplitudes and gradients without explicit reference to the total density matrix. This proves to be a particularly efficient scheme, with an intrinsic computational cost that scales linearly with the number of G -spinor basis functions. In order to validate this new implementation, incorporated in the parallel version of the program BERTHA, a detailed study of the diatomic system CsAu is also reported. Th..