Compton Profile of LiH

Abstract

The Compton profile from a single crystal of LiH has been measured with the x-ray scattering vector along the [100], [110], and [210] directions. The valence-electron contribution to the measured profile is in marked disagreement with that calculated from the crystal-field wave functions of Hurst. The observations indicate that the valence-electron momentum distribution is broader in momentum space than the distribution obtained from a superposition of ${\mathrm{H}}^{-}$ and ${\mathrm{Li}}^{+}$ wave functions for either the free ions or the ${\mathrm{H}}^{-}$ ion in a ${\mathrm{Li}}^{+}$ point-lattice crystalline field. It appears that a more extensive calculation is required to get agreement with both the x-ray scattering factor and Compton-profile measurements. For the three crystal orientations studied, the Compton profiles show only a small anisotropy.