Improved dipole moments by combining short-range gradient-corrected density-functional theory with long-range wave-function methods

Previously proposed schemes of coupling short-range density-functional-based with long-range wave-function-based methods are tested for the notoriously difficult case of correctly describing the charge distribution in compounds containing late transition elements. We show that for the dipole moments of the group-11 transition metal hydrides and halides the recently developed Coulomb-attenuated Becke three-parameter Lee-Yang-Parr hybrid functional already leads to a substantial improvement compared to other density functionals. Further improvement is achieved by combining a gradient-corrected short-range functional of the Perdew-Burke-Ernzerhof type with coupled-cluster theory. The results clearly demonstrate that mixing of long-range ab initio Hartree-Fock and post-Hartree-Fock methods helps to remove deficiencies of current density functionals.