POLARIZATION SPECTROSCOPY OF NS2 IMPURITY IONS IN ALKALI-HALIDES

The luminescence of the alkali halides doped with ns2 ions is studied in a wide temperature region by the methods of time-resolved polarization spectroscopy with the use of magnetic and electric fields. It is established that the structure and properties of relaxed excited states (RES) of all the centers investigated may be adequately described in terms of a theory which considers a strong Jahn-Teller effect as the main interaction in the RES. Very interesting effects and processes are also observed, which are caused by some weaker interactions: by spin-orbit, hyperfine and vibronic interactions that mix different excited states of the center; by the influence of the defect associated with an ns2 ion, etc. This paper is based mainly on the experimental results obtained by the author and her co-workers during the last 15 years.