RELATIVISTIC EFFECTS ON THE COMPTON PROFILE OF POLYCRYSTALLINE GOLD

The spherically averaged Compton profile (CP) for gold is calculated on the basis of the relativistic density-functional theory in the local-density approximation (LDA) with a warped muffin-tin potential. In the all-electron self-consistent procedure, the core levels are calculated by means of the Dirac operator while the valence levels are determined by a relativistic generalization of the modified augmented plane-wave (MAPW) method using the reduced 2 x 2 matrix Hamiltonian according to Foldy and Wouthuysen. The CPs of the core electrons are found to be in surprisingly good agreement with the orbital CPs of the relativistic Hartree-Fock calculation for atomic gold by Biggs et al. The relativistic corrections on the valence CP due to mass-velocity and the Darwin term are investigated separately and comparisons with non-relativistic calculations are made.