Green emitting molybdate complexes in PbWO4—results of an ODMR study

Abstract The nature of the green emission of PbWO 4 is still under discussion, models ranging from WO 3 groups over lead deficient phases to local distortions towards a wolframite structure. In CaWO 4 and PbMoO 4 optically detected magnetic resonance proved, using resolved Mo hyperfine structure, that tetrahedral MoO 4 complexes give rise to a green luminescence. Based on this, we have performed such experiments on a series of PWO samples from various sources and with different dopants. In all cases, we find resonances typical for MoO 4 groups, however, with strongly varying intensity depending on the Mo content of the crystals. These ODMR signals are connected with a luminescence band with a half width of 0.43 eV peaking at 508 nm.