Spectroscopic Investigation of Cu+ and Ag+ Centres in Alkali Halides under High Hydrostatic Pressure

The effect of hydrostatic pressure up to 6000 kp/cm2 on the excitation and emission spectra of Cu+ and Ag+ centres in alkali halides is studied. In all crystals, the blue shift of both the emission band and the low‐energy side of the excitation spectrum is observed, the emission band shift being greater. The analysis basing on a single configuration‐coordinate model shows that the pressure shifts of Cu+ and Ag+ spectra are caused mainly by the change (increase) of the pure‐electronic transition energy. The results obtained confirm the conclusion about the genetic relation between these spectra and the electronic transitions d10 ⇄ d9 s in free Cu+ and Ag+ ions. For a few crystals the effect of pressure on the luminescence decay is measured. Possible reasons for the change of τ by the lattice compression are discussed.