  Since a rigorous microscopic treatment of a nematic fluid system based on a
pairwise interaction potential is immensely complex we had introduced a simple
mean field potential which was a modification of the Maier-Saupe potential in a
previous paper. Building up on that here we have modified that potential to
take into account the various aspects of a smectic A-nematic phase transition.
In particular we have studied the dependence of the phase transition on the
coupling coefficient between the nematic and smectic order parameters which in
turn depends on the length of alkyl chain, existence of tricritical point,
variation of entropy and specific heat as well as the dependence of the phase
transition on pressure.
