Study of the Dynamic Jahn-Teller Effect and the Far-infrared Spectra in ZnSe∶ Fe2+

A great interest has been recently devoted to the Van Vleck semimagnetic semiconductors which exhibit interesting magnetic and magneto optical properties. However, the far-infrared spectra in the Van Vleck semimagnetic semiconductors ZnSe∶Fe2+do not fitthe standardized crystal-field theory and in particular exhibit additional lines. The Hamiltonian matrices for the ground state5D of 3d4/3d6ions are derived by taking into account the cubic crystal field interaction the spin-orbit coupling and the dynamic Jahn-Teller effect, as well as the far-infrared spectra of ZnSe∶Fe2+are studied b using these matrices. The theoretical results being in good agreement with the experimental observations indicate that the far-infrared spectrum levels in ZnSe∶Fe2+, which do not exist for the standard crystal-field theory, are due to the dynami Jahn-Teller effect in this crystal. In addition, some theoretical Jahn-Teller splitting presented are in need of further theoretical and experimental studies. The presentmatrix is useful for the study of fine structure spectra, EPR parameters an dynamic Jahn-Teller splittings of 3d4/3d6ions in the cubic crystal field.