A DIRECT CALCULATION METHOD FOR SPECTRAL PARAMETERS OF THE TRANSITIONBETWEEN (4)T(2) AND (4)A(2) IN CHROMIUM-DOPED CRYSTALS

A method for directly calculating the Huang-Rhys S-factors and the eff ective phonon energy homegaBAR as well as the linewidths of 4T2 emissi on in chromium-doped oxides and fluorides is introduced. By use of thi s method, the experimental data required are only the wavelengths of t he absorption and the emission peaks of the transitions between 4T2 an d 4A2. The calculated values agreed very well with the experimental da ta published in the literature. Comparing the calculated linewidth wit h the experimental linewidth, one can also obtain information about wh ether the spectra result from one or more than one active centre and t he existence of disorder in the crystal field of the active centres.