The line shape and zero-phonon line of the luminescence spectrum from zinc tungstate single crystals

The blue and infrared (IR) bands of the photoluminescence spectra in the temperature range 11-430 K and excitation bands at 77 and 300 K of zinc tungstate single crystals have been studied. The line shape, obtained from the theory of lattice relaxation and multiphonon transitions, is compared with the experimental results. The temperature dependences of the intensity, the peak position and the line width of the zero-phonon line associated with the IR emission band are investigated experimentally. The results obtained are discussed in terms of the theory of linear and quadratic electron-phonon interactions.