On the oscillator strength of F centers in alkali halides

A radiochemical method, previously applied to NaCl, KCl, and KBr crystals has been used to determine the oscillator strength ƒ of F‐centers in RbCl. By extending theoretical calculations carried out by Smith and Spinolo, and by Iadonisi and Preziosi, estimates of ƒ for several alkali halides, including those previously mentioned, have been computed. The experimental results agree very closely with those obtained by Rauch and Heer and are in good accord with the theoretical estimates (the theoretical results are reported in brackets). ƒNaCl= 0.64 ± 0.02 (0.57); ƒKCl= 0.68 ± 0.02 (0.61); ƒKBr= 0.72 ± 0.02(0.57); ƒRbCl= 0.51 ± 0.05 (0.57). The experimental and theoretical results seemed to bear each other out and led to the conclusion that the ƒ values given in the literature, except those by Rauch and Heer, are overestimated.