Theoretical study of local environment of Mn(2+) in two different tetragonal sites in Cs(2)NaLaCl(6) elpasolite.

A theoretical method for investigating the inter-relation between the electronic and the molecular structures of a 3d(5) ion in a tetragonal ligand-field has been established on the basis of a 252×252 complete energy matrix. By means of this method, the local lattice structures of Mn(2+) in two different tetragonal sites in Cs2NaLaCl6 elpasolite are determined by the experimental EPR spectra. The Mn(2+)-Cl(-) distances have been obtained as: R1=3.

Theoretical studies of EPR spectra and defect structure for Er3+ center in lithium niobate.

The optical and EPR spectra of octahedral Er(3+) center in LiNbO(3) have been studied by diagonalizing 364 x 364 complete energy matrices. The new set of crystal-field parameters that can well account for the Stark levels and EPR parameters have been obtained for Er(3+) ions in LiNbO(3). Simultaneously, by simulating the most reliable six-order parameter B(60) obtained, we have presented the evidence that the Er(3+) ions do not occupy the actual Li(+) site, but have a displacement along the C(3)-axis away from the Li(+) center by about 0.