Dielectric relaxation and molecular conformational energy of some arylazo benzothiazine derivatives

We carry out semi-empirical calculations on some arylazo benzothiazine deri vatives to obtain the energy barriers for internal rotation and dipole mome nts, using the PM3 Hamiltonian. By means of the correlation function method and some probabilistic procedures we describe then the dielectric relaxati on of these molecules and we try to explain what the contribution of differ ent relaxation modes is in the process of relaxation. Moreover, we account for the consequences of the nonrigidity of the molecules in dielectric resp onse. (C) 2000 Elsevier Science B.V. All rights reserved.