[An investigation of the optical spectra and the EPR spectrum of Ni2+:CsMgCl3].

A method which can calculate accurately the zero-field splitting parameter D and the g-factor is founded by applying the energy matrix elements, including Coulomb interaction and spin-orbit coupling of the strong-field coupling scheme for d2 (d8) electron configuration in trigonal crystal field and adopting the method of complete diagonalization. In the calculation, all spin singlet states and spin triplet states hae been considered, then the calculation result is exact. The present theory shows that g parallel > g perpendicular, D < 0 or g parallel < g perpendicular, D > 0 are due to the different distortion of ligands along C3 axis. The optical spectra and the EPR spectrum of Ni2+:CsMgCl3 with D3d symmary are calculated by using the theory. The agreement of theory with the experiment shows that the present theory is reasonable.