R-Center Production in Alkali Halides

Abstract

The suggestion that both the $R_1$ and $R_2$ bands in colored KCl crystals may be due to transitions of the $F_2$ center is considered. Formation mechanisms in support of this view are presented which are consistent with (1) the behavior of the $R$ and $M$ bands during $F$-light irradiation, (2) the observed decrease of the $R$ bands and increase of the $M$ band produced by heating, and (3) the photoconductivities measured for the $R_1$ and $R_2$ bands.