The energy spectrum of vibronic states of Jahn-Teller's ion

It is shown that current experimental data on the EPR spectrum of the copper two-valent ion in the octahedral coordination do not agree with the two-mode cluster model of the Jahn-Teller effect in a number of parameter. In this connection the present paper proposes a modified cluster model allowing for the population of a large number of weakly split vibronic states . Within the model the experimentally observed peculiarities of the Jahn-Teller effect manifestation in the EPR spectrum are explained