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Single Phonon X‐ray Scattering from Alkali Halides II. Ionic Deformation Scattering
Author(s) -
Reid J. S.
Publication year - 1974
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.2220640107
Subject(s) - antisymmetric relation , scattering , alkali metal , shell (structure) , deformation (meteorology) , intensity (physics) , halide , phonon , phenomenological model , symmetry (geometry) , coupling (piping) , physics , nearest neighbour , molecular physics , atomic physics , condensed matter physics , materials science , chemistry , optics , quantum mechanics , geometry , inorganic chemistry , mathematics , composite material , artificial intelligence , meteorology , computer science , metallurgy , mathematical physics
Methods and difficulties of comparing experimental and theoretical deformation scattering intensities are considered. The phenomenological approach is developed through the model of centrosymmetric deformations which has previously been used to describe experimental intensities in NaCl and NaF. This model is extended beyond nearest neighbour interactions and reapplied to the experimental intensities. The nearest neighbour coupling parameters change substantially. Antisymmetric deformations are examined through the widely used rigid shell models. For NaCl and NaF, values of the scattering intensities along symmetry directions are calculated, assuming a simple interpretation of the shell model parameters. The large discrepancy between the small intensities of the shell models and the arger intensities of the phenomenological models is discussed and it is concluded that more small sin θ/λ experimental intensity measurements are urgently required.