Low frequency transition between vibronic levels of V9+2 in crystalline V2O5 from electron spin-lattice relaxation measurements

2014 We have established the existence of a characteristic energy (0.0013 eV) in undoped crystalline V2O5, by measuring, between 1.3 K and 50 K, the relaxation time of the paramagnetic defect detected at g = 2. In order to interpret this result, we have examined the different models which have been proposed in the past for this defect, and which all imply the existence of a V9+2 molecular ion; taking the recent arguments of Clauws et al. into account, we have finally adopted the model proposed by Perlstein. The energy 0394 cannot correspond to the splitting between the bonding and antibonding levels of V9+2, since a calculation indicates that the separation between these levels is 0.16 eV. In our interpretation, 0394 is the energy separation between the ground vibronic level and the first excited vibronic level of V9+2. J. Physique 44 (1983) 691-698 JUIN 1983, 1