Determination of the electron momentum distribution in A1_2O_3 using X-ray noncoherent scattering data

摘要

Valence electron momentum distribution functions of ionic oxide A1_2O_3 were investigated using the measured and calculated Compton profiles. Compton lines were measured using the X-ray three-crystal spectrometer. The scattering angle was 155 deg. Monochromatic AgK and M_0 (lambda = 0,056 nm, hv= 22,46 keV) radiation was used. Monochromatization of X-ray radiation was achieved by using Ceylon graphite. LiF served as the crystal-analyzer. The measured Compton lines were normalized using noncoherent scattering factors calculated taking into account ionization of atoms. It was found that, although ionic binding predominates in A1_2O_3 crystal lattice, experimental results are best explained by a theoretical model based on an assumption that one of electrons lost by aluminum does not participate in ionic binding with oxygen.