Local structure and EPR g factors for KAl(MoO4)2:Cr3+ and RbIn(MoO4)2:Cr3+ systems

For a d3 configuration ion, the 120 × 120 complete energy matrix which contains the electron-electron repulsion interaction, the ligand field interaction, the spin-orbit coupling interaction as well as the Zeeman interaction, has been established. By diagonalizing the complete energy matrix, local structure and EPR g factors for Cr3+ ions doped in KAl(MoO4)2 and RbIn(MoO4)2 have been investigated, respectively. It is found that the orbit reduction effect is very important to understand the EPR g factors for Cr3+ ions doped in KAl(MoO4)2 and RbIn(MoO4)2, and some characteristics of orbit reduction on the EPR g factors are discussed firstly. Simultaneously, by simulating the calculated optical spectra and the EPR spectra data to the experimental results, we obtain the local structure parameters R = 2.043 Å, θ = 53.5940° and R = 2.065 Å, θ = 56.0434° for Cr3+ ions doped in KAl(MoO4)2 and RbIn(MoO4)2, respectively. The calculated results show the local lattice structure of the octahedral Cr3+ centers in KAl(MoO4)2 and RbIn(MoO4)2 exhibit an elongation and a compression distortions, respectively.