Anisotropy in the momentum density of tantalum

The [1 0 0], [1 1 0] and [1 1 1] directional Compton profiles of tantalum have been measured, at an intermediate resolution, with 661.65 keV γ-radiation and a well-defined scattering vector. We have also computed the Compton profiles within the framework of pseudopotential using CRYSTAL03 code of Torino group. The measured anisotropy is found to be smaller to that predicted by our pseudopotential computations and also the available augmented plane wave (APW) calculations. A comparison of the absolute theoretical and the experimental profiles shows clearly for the first time the importance of anisotropic electron–electron correction effect in the third series transition metals. A quantitative comparison between the experimental and theoretical directional difference profiles reveals some accurate information about the Fermi surface topology of tantalum.