Electronic spectra and co-operative optical transitions in CaWO 4:Tb 3+ single crystal

Abstract

The absorption, fluorescence and excitation spectra of CaWO 4:Tb 3+ single crystal were studied at 300 and 77 K. The polarization studies on laser excited fluorescence spectra were also carried out at 77 K. These studies led to the complete identification of two fluorescing states viz. 5 D 4 and 5 D 3 and of all the 7 F ground multiplets of Tb 3+ ions. Co-operative electronic transitions were observed for the first time in the low dopant concentration crystal and inferred as due to multi-polar interactions.