Electronic structures and color centers of PbWO4 with lead vacancy

Abstract

The electronics structures and absorption spectra of polarized light for the PWO crystal containing VPb2- have been calculated using CASTEP code with lattice structure optimization. The optimized lattice structures around lead vacancy in the PWO have been obtained. The color center models and their corresponding absorption spectra have been proposed according to the experimental results of the lattice structures and the electronic structures around the lead vacancy. The negative divalent VPb2- should trap two holes to maintain the local neutrality. The possible way of the formation of the hole centers is one trapped hole shared by two O2- ions nearest to VPb2- and other one shared by another two O2- ions nearest to VPb2- forming ［O23--VPb2--O23-］. The different ways of O2- ions trapping the holes will form different color centers corresponding to different absorption bands. The color center models around VPb2- have been proposed.