Optical Spectrum of Trivalent Dysprosium in Calcium Tungstate,

The optical absorption and fluorescence spectra of Dy3 in single crystals of CaWO4 have been examined. The measurements were made using 0.1 and 0.5 atomic percent Dy3 in crystals at temperatures of 2, 25, and 85K, and they were made over wavelength regions corresponding to transitions to all the 6H ground term energy levels. A definitive identification of all the energy levels of the ground term was not possible because of some term mixing and some mixing of the o and n polarization measurements. Possible identifications of the energy states were obtained by comparisons made with calculated energy states however. The calculations were made using the method of Karayianis in which an effective Hamiltonian is diagonalized in a basis of Russell-Saunders wave functions for the entire ground term of Dy3. This calculation includes all the J-mixing effects of the crystal field and the effects of spin-orbit interaction to better than second order. Calculated g factors for the lowest lying energy states were found to be quite sensitive to changes in the Blm. Hence these data and results of earlier EPR studies are not yet able to allow definitive symmetry properties to be established for the ground state. Author