An ab initio Hartree-Fock investigation of galena (PbS)

Ab initio Hartree-Fock (HF) theory has been applied to galena (PbS). Pseudopotentials are used to describe the Pb core states and Gaussian basis sets have been developed for S (all electron) and Pb (valence only). The effect of the approximations made (HF theory, the basis set and the pseudopotential) on the structural energetics have been examined in detail. The computed lattice constant and elastic constants are in fair agreement with experiment. The effect of basis set on these properties is minor whereas different choices of pseudopotential and correlation corrections significantly affect the results. The density of states is insensitive to these approximations and in good agreement with spectroscopic data.