Energy transfer in CaCl₂:Eu:Mn crystals

Abstract

An investigation was made of the energy transfer between Eu2+ and Mn2+ ions in CaCl2 single crystals under photoexcitation. The studies performed at several impurity concentrations and the measurements of the excitation spectra and lifetimes of the observed europium and manganese emissions in the temperature range 11-300 K suggest that the Eu2+ to Mn2+ energy transfer process taking place in the authors slightly doubly doped crystals of CaCl2:Eu:Mn occurs in small complexes of Eu-Mn which are formed in the lattice. The spectroscopic data obtained substantiate the ionic radius criterion proposed by Rubio et al. (1988) to predict pairing between two impurity ions in a solid material between which energy transfer is desired.