Compton spectroscopy analysis of Eu2O3and applicability of first and second order GGA in deducing electron momentum densities

To validate the available experimental momentum densities (measured using 662 keV radiations) of a rare earth oxide Eu2O3, first and second order generalized gradient approximations (GGA and SOGGA) of density functional theory (DFT) have been employed to compute Compton profiles (CPs). The DFT computations have been performed within linear combination of atomic orbitals (LCAO) method. It is found that both the computed CPs reconcile with the experimental Compton line shape. Present comparison shows almost similar role of exchange and correlation potentials of GGA and SOGGA in predicting the electronic structures of the studied oxide, admittedly with a marginal better agreement with first order GGA approximation. Also, the anisotropies in CPs (J110-J100, J110-J100and J111-J110) from GGA and SOGGA are found to be identical which strongly support the present investigations. The Fourier transform of CPs leading to real space B(z) functions concludes a metallic nature of Eu2O3.