Wavefunction-based <i>ab initio</i> correlation method for metals: application of the incremental scheme to Be, Mg, Zn, Cd, and Hg

Abstract

Ab initio electron correlation calculations based on quantum-chemical methods are successfully applied to a metallic system. To deal with the two distinct problems that occur in metals, the difficulty of localization of the orbitals and the generation of clusters with neutral atoms in the center, we suggest an embedding scheme which has itself no metallic character but can mimic the metal in the internal region, where the atoms are correlated. The long range non-additive contributions of metalicity and correlation are treated with the method of increments. The approach has been tested on the group 2 and 12 metals (Be, Mg, Zn, Cd, and Hg). The obtained ground-state properties are shown to agree well with the experimental values. Moreover, taking into account the advantage of the method of increments to analyse the individual contributions to correlation energy it is possible to clarify some aspects of the structural features of the group12 metals.