Dynamical Jahn-Teller Effect on the Fine Structure Lines of Transition Metal Ions (Abstract Only)
An experimental study under uniaxial stresses and a theoretical analysis of the zero-phonon lines of the lowest orbital triplet levels of Mn++ in ZnSe and ZnS were reported in this seminar. In the case of the 4T2 level, it was shown that a classical model in which vibronic interactions are neglected must be rejected. Then, it was shown that the hypothesis of strong Jahn-Teller interactions is consistent with the zero-stress spectrum but inconsistent with pressure-induced splittings and polarizations. Finally, a correct interpretation of all experimental results was elaborated by considering a medium coupling to E vibrational modes, and the importance of intensity transfer from the zero-phonon lines to the phonon-assited lines was demonstrated. In the case of the fluorescent level 4T1 in cubic ZnSe and ZnS, it was shown that the two fine-structure lines can be interpreted by Ham’s model corresponding to a strong Jahn-Teller coupling with E symmetry modes. A comparison was made of the Jahn-Teller effect in the lowest 4T1 and 4T2 states of Mn++ in ZnSe and ZnS. Finally, the Jahn-Teller effect for d4-d6 and d3-d7 ions was briefly reviewed.