Luminescence of single crystal CaMoO4

Abstract CaMoO4, powellite, is a member of the do, self-activated, family of phosphors for which the luminescence properties must be interpreted by a model containing both metal and ligand orbitals. The model was tested by measuring polarized luminescent emission spectra on a single crystal of CaMoO4. The emission band wavenumber is independent of polarization but the relative intensity is strongly dependent on both excitation and emission polarization. The spectra support a model of energy levels derived from ligand to metal charge transfer. However, the effect of the tetragonal crystal field appears in the relative intensities rather than in band splitting.