抄録
Earlier workers observed that in the initial stages of room-temperature F-band irradiation of additively-colored, freshly-quenched alkali halide crystals a low energy broadening of the F band appeared. Here this broadening in KCl was measured and similar results for two very different sodium concentrations were obtained. This indicates that sodium FA centers are not responsible for the effect. The “resonance broadening” due to the dipolar interaction of two F centers was calculated. It was found that this mechanism could account for the observed phenomenon if most of the F centers were about 3 nearest neighbors apart, or if 5% of them were about 2 nearest neighbors apart. Published experimental results indicate that in the early stages of irradiation few of the F centers are this close together, although a number as small as 5% is not necessarily ruled out. Other possible explanations of the experimental results are discussed.
