The tetragonal symmetry of the Pb++-centre in KCl

Abstract

The polarization characteristics of the KCl:Pb phosphor are investigated. The measurements are explained with a configuration coordinate model. With the assumption that the Pb++-centre has the symmetry 4mm, the first excited state of the Pb++-ion 3P1 will be split into two sublevels with E- and A2-symmetry. Absorption occurs between the ground state and the two excited sublevels at 4.49 eV and 4.53 eV. Emission occurs only from the lowest sublevel with E-symmetry. The model proposed here is compared with the model proposed by Trinkler.