The electronic structure and absorption spectra for the perfect CaWO4 and the
CaWO4 containing oxygen vacancies, VO
2+, were calculated using density
functional theory code CASTEP with the lattice structure being optimized. The
results indicate that the CaWO4 crystal containing VO
2+, an additional absorption
spectrum in the region of visible light. And the absorption spectrum can be fit into
two Gaussian-shape absorption spectra with peaks at 360 and 415nm. These peaks
were located at the experimentally observed position. It was predicted that the 340 and the 420nm absorption spectra were related to the existence of VO
2+ in the
CaWO4 crystal.
First-Principles Study on Electronic Structure and Absorption Spectra for the
CaWO4 Crystal with Oxygen Vacancy. Z.Shao, Q.Zhang, T.Liu, J.Chen:
Computational Materials Science, 2008, 43[4], 1018-21