Core polarization corrections on the relativistic core effective potentials formalism

Abstract

The ab initio shape-consistent Relativistic Effective Potential (REP) formalism, recently improved, implicitly incorporates relativistic corrections. However, since the frozen core approximation is assumed, intershell correlation can not be taken into account. This is a serious drawback in REP treatments on alkali systems, where the core polarization is especially pronounced. An easy way to correct the REP method by adding to the core operators a phenomenological core polarization potential is proposed. With no adjustable parameters, the corrected REPs account for a major contribution to the full core/valence correlation at virtually no computational cost.