Ground state properties of heavy alkali halides

TL;DR

This paper presents advanced calculations of heavy alkali halides, incorporating relativistic effects and electron correlations, resulting in improved accuracy of lattice constants and providing new ab-initio data on polarizabilities and van der Waals coefficients.

Contribution

It extends previous work by including relativistic effects and electron correlations in calculations of heavy alkali halides, improving accuracy and providing new ab-initio data.

Findings

Hartree-Fock lattice constants deviate up to 7.5% from experiments

Correlation effects reduce deviations to a maximum of 2.4%

Provides ab-initio data for polarizabilities and van der Waals coefficients

Abstract

We extend previous work on alkali halides by calculations for the heavy-atom species RbF, RbCl, LiBr, NaBr, KBr, RbBr, LiI, NaI, KI, and RbI. Relativistic effects are included by means of energy-consistent pseudopotentials, correlations are treated at the coupled-cluster level. A striking deficiency of the Hartree-Fock approach are lattice constants deviating by up to 7.5 % from experimental values which is reduced to a maximum error of 2.4 % by taking into account electron correlation. Besides, we provide ab-initio data for in-crystal polarizabilities and van der Waals coefficients.