Theoretical Examination on Optical and Magnetic Behaviors of Cu²⁺ Ions in Cs₂CuCI₄

A set of formulas on the energies of d - d transition, the EPR g-factors, and the magnetic susceptibilities has been deduced for d⁹ ions. The results calculated by using these formulas are in good agreement with the experimental findings of the Cs₂CuCI₄ crystal. This shows that the optical and magnetic properties can be explained by using both the approximate parame-terized d-orbital and the diagonalization procedure of the complete energy matrix. Moreover, for obtaining more pieces of information, the lower symmetry and spin-orbit coupling need to be considered in the theoretical calculation.