Pressure effect on the smectic-A-isotropic phase transition.

We examine the effect of pressure on the smectic-A-isotropic phase transition within the Landau phenomenological theory. The influence of pressure on the smectic-A-isotropic phase transition is discussed by varying the coupling between the orientational and the translational order parameter. The transition is found to be of first order even at elevated pressure. The pressure dependence nonlinear dielectric effect in the isotropic phase of the smectic-A-isotropic transition is calculated. The theoretical results are in good qualitative agreement with available experimental results.