V Bands in RbI Crystals Containing Excess Iodine

Abstract

Optical properties of RbI crystals, which were additively-colored with iodine or electrolytically-colored by the pointed-anode method, have been studied. After coloration, two bands assigned as V₂ and V₃ bands are observed at 358 and 287 nm, respectively, at 77 K. Dichroism is induced in both bands at 77 K by irradiation with the [110]- or [100]-polarized V₂ light. Upon irradiation with the V₃ light at 68 K or at 125 K, the V₂ and V₃ bands are bleached and a few bands are formed simultaneously in the uv and visible regions. In addition to the properties of the V₂ and V₃ bands, spectral positions of the newly formed bands are consistent with the previous results of KI. It is concluded then that V centers introduced into halogen-excess crystals of RbI and KI have the same structures.