Theoretical investigations on the electron paramagnetic resonance for Cr3+ in SrLaGaO4 and Cs2CdCl4 crystals

On basis of crystal field theory, considered the radius and valence charge of transition metal ion are not the same with that of the substituted one in tetragonal crystal system, the local structure extension model of transition metal ion (3dn/10-n) has been built. Furthermore, in a tetragonal strong field scheme by semi-SCF d-orbit wave functions model of free ions, high-order perturbation method, point-charge crystal field model and local structure extension model, the EPR parameter of SrLaGaO4:Cr3+ and Cs2CdCl4:Cr3+ have been explained. The calculated results agree well with the experimental findings, which indicated that the extension model used in this paper was reasonable, and it could be fit for other tetragonal crystal system.