Ab initio calculations on the local structure and the 4f–5d absorption and emission spectra of image-doped YAG

The image absorption and emission spectra of image-doped YAG image are simulated with a quantum chemical ab initio embedded cluster approach applied to image substitutional defects of image local symmetry. The only empirical information used is the structure of the pure host. The simulated absorption spectrum is calculated with overestimations of 2300–image, which became image in the luminescence. The three image observed absorptions were assigned and the energies of the two remaining ones, which are hidden by the absorption of the pure host, were predicted. The lowest image emission was found to take place from image (image) and the next emission from image (image). Good absorption and emission band shapes and relative intensities are obtained. A large underestimation of the Stokes shift is found, which suggests an underestimation of the relaxation on the emitting state.