Abstract
The results of optic and EPR measurements are presented. The transmition bands observed during optic measurements (above and below Tc) have been identified. It is shown that the phase transition, taking place at 180 K reflects itself only in a small parallel shift of the whole spectrum towards higher frequencies. Temperature dependence of the EPR spectrum reveals not only the transition at 176 K but two other anomalies detected at T1 = 156 K and T2 = 285 K. An outline of the theory predicting the existence of these anomalies is discussed in terms of the so-called cluster model.