Mollwo-Ivey relation between peak color-center absorption energy and average oxygen ion spacing in several oxides of group-II and -III metals

Abstract

A simple relationship similar to that reported by Mollwo and Ivey relating peak absorption energy to the lattice parameter in the alkali halides has been noted for several oxides of group-II and -III metals, including BeO, ${\mathrm{Al}}_{2}$${\mathrm{O}}_{3}$, Mg${\mathrm{Al}}_{2}$${\mathrm{O}}_{4}$, ${\mathrm{Y}}_{3}$${\mathrm{Al}}_{5}$${\mathrm{O}}_{12}$, and most of the cubic alkaline-earth oxides. Instead of the lattice parameter, the average oxygen spacing, which may be defined independent of crystal structure, is taken here as the independent variable.