A Theoretical Study of Diffuse Scattering by Clusters in Alkali Halides

Abstract

It is shown that in the case of dipoles located in one sublattice (divalent impurity with compensating vacancy), or its complexes, diffuse scattering very near to the Bragg reflections is determined only by short range non-Coulomb forces affecting the lattice by the defect; in the case of dipoles in different sublattices (divacancies) or their complexes, the electrostatic forces also make a contribution to the amplitude of scattering. Strong compensation of contributions of this forces in the range near the Bragg reflection causes low cross-section of scattering by divacancies and their complexes, in comparison with the cross-sections by vacancies and divalent impurities with vacancies. In the case of the diffuse scattering far away from the Bragg reflection the cross-sections of the same defects have a comparable value. The amplitude of near-to-Bragg-reflection scattering on clusters is proportional to the number of dipoles in the cluster. n o~a 3 a~0 , YTO ecm B cnygae nnnonefi, pacnonoxeaebrx B o n~o i i noApellreTKe (AByxBaneHrHas IIpAMeCb C KOMIIeHCApyIOmefi BaKaHCAefi) AJIII AX KOMnJIeKCOB, AAl$l$y3HOe OKOJIO6p3rrOBCKOe