Raman study of V-centres in X-irradiated KI

Raman experiments were carried out on KI, X-irradiated over a range of temperatures for which V-centres are created. After X-irradiation at 190K, a Raman band was observed at 112 cm -1 , attributable to the 'symmetric' stretching vibration of an I 3 - molecular ion and responsible for the 335 nm absorption band. The Raman spectrum of KI X-irradiated at room temperature is composed of two sharp lines at 180 and 189 cm -1 as in molecular I 2 crystals, which is in agreement with the formation of large iodine aggregates.