Lattice dynamics in terms of localized orbitals

Abstract

The formalism of molecular obitals, developed by Adams, is utilized for a description of the lattice dynamics of crystals for which charge overlap between lattice neighbors is small, e.g., ionic or rare-gas crystals. Under an approximation introduced by Kunz, the expectation value of the interaction potential for molecular orbitals at different sites is neglected. In order to improve on this approximation in the present derivation, a semiempirical potential is introduced. The formulation leads to a screened electron-phonon coupling. The result is compared with other quantum mechanical and classical approaches to lattice dynamics.