Density functional LCAO calculations of periodic systems. Effect of an ‘a posteriori’ correction of the Hartree-Fock energy on the physical properties of ionic sulfur compounds

Density functional theory is taken into account to correct ‘a posteriori’ the total energy calculated with ab initio Hartree-Fock theory. Two models are adopted: the first one is the local density approximation parametrized by Ceperley and Alder while the second one is non-local and corresponds to the formulation proposed by Perdew. The changes in physical properties of ionic sulfide compounds (equilibrium geometry, formation energy, elastic constants, phase transition B1 → B3 in MgS and surface relaxation) associated with the electronic correlation are evaluated.