A QUANTUM-STATISTICAL MODEL OF A 3-DIMENSIONAL LINEAR RIGID ROTATOR IN A BATH OF OSCILLATORS .2. THE ELECTRICAL BIREFRINGENCE IN RELAXATIONREGIME

The Kerr effect relaxation resulting from the sudden removal of a DC f ield previously applied to a system of dilute rigid linear polar rotat ors in a sea of non-interacting bath harmonic oscillators is presented . In the quantum mechanical model proposed, we take account of permane nt and induced dipole effects while the inertial effect of the bath is described by a collision operator. Hyperpolarizabilities are neglecte d. We use a generalized master equation governing the evolution of the rotator probability density operator to calculate the Kerr relaxation function Phi(t). In the search for this function, we define matrix el ements phi(l,l)(t) and phi(l,l+2)(t) whose knowledge at all times t, c ompletely gives Phi(t). We recover the classical limits of the quantum expressions. A quantum result valid for the rotating wave approximati on limit is given. This paper is a logical continuation of our recent work.