Lattice dynamics of alkali hydrides and euterides with the NaCl type structure

Publisher Website
Google Scholar
Abstract
The deformation dipole model, the shell model, and also extended versions of these models have been investigated for the lattice dynamics of LiH and LiD. A deformation dipole model with 13 adjustable parameters gave the best fit to the phonon dispersion of LiD known from neutron and Raman experiments. The model has been used to compute elastic and dielectric constants, Szigeti effective charges, phonon densities of states, Debye temperatures and second-order Raman spectra of LiD and LiH. Good agreement with the experimental data was obtained. The contributions of short-range three- and four-body forces to the model force constants are discussed. First calculations of the phonon dispersion curves of the hydrides and deuterides of Na, K, Rb and Cs, which are based on shell models, are presented.