Luminescence of ZnWO₄ and CdWO₄ Crystals

The spectra of luminescence and photoexcitation as well as emission decay kinetics in various parts of spectra are investigated in ZnWO₄ and CdWO₄ crystals in a wide temperature range (4.2 to 300 K). The bands of red afterglow and of rapidly decaying violet luminescence are observed for the first time. The likeness of the emission properties of ZnWO₄ and CdWO₄ allows the explanation of the luminescence in these tungstenite type crystals in terms of configurational coordinate diagrams of self-activated radiation centre and of self-trapped exciton.