UV-VUV synchrotron radiation spectroscopy of NiWO₄

Photoluminescence and excitation spectra of microcrystalline and nanocrystalline nickel tungstate (NiWO₄) were measured using UV-VUV synchrotron radiation source. The origin of the bands is interpreted using comparative analysis with isostructural ZnWO₄ tungstate and based on the results of recent first-principles band structure calculations. The influence of the local atomic structure relaxation and of Ni²⁺ intra-ion d-d transitions on the photoluminescence band intensity are discussed. PACS: 78.55.Hx Other solid inorganic materials; 61.05.cj Electron density of states and band structure of crystalline solids; 71.20.-b X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.