Off-centre equilibrium configuration of the self-trapped exciton in alkali chlorides

Publisher Website
Google Scholar
Abstract
The structure of the self-trapped exciton (STE) in alkali chlorides has been obtained from a calculation in which the electron state and the lattice relaxation are determined simultaneously in a consistent way. The excited electron of the STE is treated with the extended-ion model and the lattice is represented by a pair potential. The results show that the STE at equilibrium is shifted off-centre, and occupies a site of symmetry C2V. The self-trapped hole (Vk centre) shifts axially by about 2 au, while the electron is centered near the nascent vacancy. The absorption energies to some of the higher excited states as well as the spin density are calculated and compared with experimental data. Some of the problems that were not resolved in earlier work are solved here.