Exact-exchange Hartree–Fock calculations for periodic systems

Abstract

Calculated directional Compton profiles for silicon are presented. The electronic wavefunction was obtained with an LCAO self-consistent field ab initio Hartree–Fock all-electron minimal-basis-set method previously described (Pisani and Dovesi 1980). Comparison is made with experimental data and with the profiles for diamond calculated in the same approximation; it is shown in particular that some definite, though minor, disagreements occur between experimental and theoretical anisotropies in the momentum distribution, which are attributed mainly to insufficient variational freedom in the calculated wavefunction.