Compton scattering study of the electronic structure of magnesium hydride

Abstract

Compton scattering measurements have been made on magnesium hydride (Mg${\mathrm{H}}_{2}$) using the 59.54-keV gamma rays from a 300-mCi $^{241}\mathrm{Am}$ source at a scattering angle of 150\ifmmode^\circ\else\textdegree\fi{}. Two different theoretical approaches have been used for comparison with the experimental data. In the first approach, the Compton profile of the valence electrons in Mg${\mathrm{H}}_{2}$ was calculated by the pseudopotential orthogonalized-plane-wave (OPW) method, including core orthogonalization. In the second approach, the Compton profile of Mg${\mathrm{H}}_{2}$ was calculated using the tight-binding linear combination of atomic orbitals (LCAO) method, including large overlaps. Both calculations yielded profiles which are in fairly good agreement with the experimental isotropic profile. The results indicate that the ionic picture of Mg${\mathrm{H}}_{2}$ is not simple since its outer electrons are extended. Possible implications of the production process of the hydride are briefly discussed.