Directional Compton profiles and the electron density distribution in vanadium

The [100], [110] and [111] Compton profiles have been derived from Compton scattering measurements made with 412 KeV 198Au γ-ray sources on single-crystal samples of vanadium. These profiles and their Fourier transforms have been compared with the predictions of APW and LCAO band-structure calculations. Both sets of calculations consistently underestimate the high-momentum component of the charge density in all three directions, but overestimate the scale of the anisotropy in the momentum density distribution. An analysis of the results in terms of an elementary atomic model based on the varying occupancy of the 3d orbitals illustrates the atomic nature of the 3d band.