Ab initio real-space Hartree-Fock and correlated approach to optical dielectric constants of crystalline insulators

In this paper we present an approach aimed at calculating the optical dielectric constant (epsilon(infinity)) of crystalline insulators both at the Hartree-Fock and correlated levels. Our scheme employs a real-space methodology, employing Wannier functions as the basic building blocks. The scheme has been applied to compute epsilon(infinity) for LiF, LiCl, MgO, and Li2O. In all the cases, results of correlated calculations, based upon systematic many-body corrections beyond Hartree Fock, exhibit excellent agreement with the experiments.