Investigation of local lattice structure around Cr3+ ions at the trigonal and tetragonal sites in RbCdF3:Cr3+ crystal

The local lattice structure and EPR, optical spectra for Cr3+ doped in RbCdF3 crystal have been studied by diagonalizing the complete energy matrices. The results show that the local structure of the Cr3+ ions in RbCdF3 exhibits a compressed distortion at the trigonal and tetragonal sites. The compressed distortion can be ascribed to the fact that the radius of Cr3+ ion is smaller than that of Cd2+ ion, and therefore Cr3+ ion will draw the fluorin ligands inwards. The variational ranges of the local structural parameters for Cr3+ doped in RbCdF3 crystal R = 1.9491 angstrom similar to 1.9814 angstrom, theta = 55.234 degrees similar to 55.286 degrees at the trigonal site and R-1 = 1.8617 angstrom similar to 1.8928 angstrom, R-2 = 1.9527 angstrom similar to 1.9851 angstrom at tetragonal site are obtained respectively, and the EPR and optical spectra agree well with the experimental results.