A quantum statistical mechanics model of a three-dimensional linear rigid rotator in a bath of oscillators: IV - steady state dielectric properties induced by AC and DC field coupling

The long time effect of a radio frequency (rf) AC held superimposed on a DC field on the electrical susceptibility and the Ken optical functions of po larizable fluids in inert solvent is analysed. The results obtained for the classical Brownian limit, valid for dense solvent media, well reproduce cl assical results published in the literature with excellent precisions in in ertia, density and temperature dependences. The low-density limit yields ab sorption-dispersion lines whose widths and shifts are density, inertia and temperature dependent. While the low density and/or large inertia susceptib ility is explicitly written as a continued fraction obtained by solving an infinite hierarchy of differential coupled equations, that of the Ken effec t is given in the form of successive convergents of the solutions of an inf inite hierarchy of differential difference triplets. The polarization/AC fi eld phase difference is analysed. The effects of the constant field strengt h and the AC held frequency on the Ken function are explored. In this paper (paper IV) the derivation of some quoted equations will intentionally be l eft out as they exist in paper III (Titantah J T and Hounkonnou M N 1997 J. Phys. A: Math. Gen. 30 6347) of which this work is its logical continuatio n.