Ab Initio Study on the Vibrational and Electronic Properties of Radiation-Induced Defects in Potassium Bromide

Abstract

The vibrational and electronic properties of several basic radiation defects in potassium bromide are computed at the quantum mechanical level using a periodic supercell approach based on hybrid functionals, an all-electron Gaussian-type basis set, and the Crystalcomputer code. The exciton energy in alkali halides is sufficient to create lattice defects, such as F–H Frenkel defect pairs, resulting in a relatively high concentration of single defects and their complexes. Here, we consider eight defects: the electronic F+ - and F-centers (bromine vacancy without and with trapped electrons) and their dimers; hole H-center (neutral bromine atom forming the dumbbell ion with a regular Br− ion.); V𝐾-center (Br−2 molecular ion consisting of a hole and two regular ions); and two complex Br−3 defects, combinations of several simple defects. The local geometry and the charge- and spin-density distributions of all defects are analyzed. Every defect shows its characteristic features in Raman spectra, and their comparison with available experimental data is discussed. --//-- This is an open-access article: Platonenko, A.; Pankratov, V.; Kotomin, E.A.; Dauletbekova, A.; Popov, A.I. Ab Initio Study on the Vibrational and Electronic Properties of Radiation-Induced Defects in Potassium Bromide. Crystals 2024, 14, 161. https://doi.org/10.3390/cryst14020161 published under the CC BY 4.0 licence,