Optical spectra of UV-irradiated rubidium and caesium nitrate crystals

Absorption spectra of RbNO3 and CsNO3 nitrate single crystals have been studied. It is stated that the photo-induced absorption in UV-irradiated samples consists of three bands. Thermal annealing and photo-bleaching (>310 nm) of the bands have been investigated. It is found that two low-energy bands are due to peroxynitrite and the high-energy band is due to the complex [NO2−⋯O]. The mechanism for the nitrite ion formation from the peroxynitrite ion and the complex has been proposed.