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Compton profile anisotropies of Na 2 S and CaF 2 in the LCAO approximation
Author(s) -
Perkkiö S.
Publication year - 1994
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221830212
Subject(s) - linear combination of atomic orbitals , compton scattering , anisotropy , momentum (technical analysis) , isotropy , atomic physics , crystal (programming language) , orthogonalization , atomic orbital , physics , chemistry , momentum transfer , electron , quantum mechanics , geometry , mathematics , scattering , finance , computer science , programming language , economics
Three directional and the isotropic Compton profiles of the isoelectronic fluorite structure compounds Na 2 S and CaF 2 are calculated using the linear combination of atomic orbitals (LCAO) approximation. The anisotropies between the directional Compton profiles are found to be confined below 2.0 at. units of momentum in the case of Na 2 S and below 3.0 at. units of momentum in the case of CaF 2 . The basic features of the anisotropies are found to be the same except near the zero momentum. Fourier transforms of the Compton profiles serve as a check of the reliability of the calculations. They reveal that orthogonalization up to the 21st order of neighbour atoms is sufficient for the [100] and [110] crystal directions but in the [111] crystal direction there are discrepancies for both compounds.