The temperature dependence of the EPR spectrum of Cu2+in ZnTiF6sdot;6H2O between 4 and 160 K

摘要

The EPR spectrum of Cu2+in the low temperature monoclinic phase of ZnTiF6sdot;6H2O was studied at 9.24 GHz between 4 and 160 K. Assuming the Jahnndash;Teller spectra to have axial symmetry,gpar;was found to vary from 2.472plusmn;0.004 at 4 K to 2.331plusmn;0.004 at 158 K, whilegperp;varied from 2.097plusmn;0.004 to 2.173plusmn;0.004 over this range. From the temperature variations of thegvalues, the lowering of the energy Dgr; of one potential well associated with the Jahnndash;Teller distortion compared to the other two was found to be approximately 143 cmminus;1. It is shown that an apparent decrease in Dgr; with increasing temperature above 100 K could be due to the presence of an excited vibronic state about 170 cmminus;1above the ground state. The variation of Verbar;Apar;Verbar; from (107plusmn;1)times;10minus;4cmminus;1at 4 K to (53plusmn;3)times;10minus;4cmminus;1at 158 K agreed with predictions based on the temperature variation of thegtensor.