Ground-state properties of heavy alkali halides

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, and 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 are reduced to a maximum error of 2.4% by taking into account electron correlation. In addition, we provide ab initio data for in-crystal polarizabilities and van der Waals coefficients.