Optical absorption in crystals and solutions of potassium halides with lead halide impurity

Using a spectrophotometric method of determining lead concentrations, the relation between the optical absorption of alkali-halide crystals with PbCl₂ impurity and that of the corresponding aqueous solutions was investigated. It was shown that the differences in the position of absorption maxima of (MHal_n)^m- complexes are determined by the effect of water molecules, and not by the structure of the complexes. It is established that the long-wave absorption band in the crystal (273 nm in KCl + PbCl₂) is due to the interaction of lead ions with anions, independently of the nature of the distribution of the impurity in the crystal.Translated from Izvestiya VUZ. Fizika, No. 12, pp. 71–76, December, 1971.