ON THE BEHAVIOR OF THERMOACOUSTIC PARAMETERS LIQUID-CRYSTALS

Thermoacoustical parameters of liquid crystals are evaluated in terms of the coefficient of volume expansivity. The MOELWYN-HUGHES parameter has been utilized to estimate a number of thermoacoustical parameters namely the isothermal, isobaric, and isochoric Gruneisen parameters, the repulsive exponent of intermolecular potential. the molecular cons tant, the fractional available volume, the Sharma constant, and Anders on-Gruneisen parameter for a few liquid crystals at different temperat ures. At the transition temperature when the mesogen transists from a highly disordered isotropically liquid state to a more ordered and den se nematic state, alpha exhibits a high value and this high value in a lpha causes a sharp fall in S-0 and enables to establish the transitio n temperatures more precisely is mesogen. It is noticed that S-0 also exhibits pretransitional temperature as alpha does. In all these syste ms the S-0 parameter, which is a characteristic constant imparts, on t he average a constant value of 1.11 +/- 0.01 both in the isotropic and nematic phases. The general behaviour of other thermoacoustical param eters have been clearly demonstrated.