Computer simulation studies of anisotropic systems. XXXII. Field-inductionof a smectic A phase in a Gay-Berne mesogen

Molecular field theory predicts the induction of a smectic A phase by the a pplication of a field, either magnetic or electric, to a nematic phase. Thi s intriguing behavior results from an enhancement of the orientational orde r which is coupled to the translational order and so shifts the smectic A-n ematic transition. To test this prediction we have investigated a system of Gay-Berne mesogenic molecules subject to an applied field of second rank u sing isothermal-isobaric Monte Carlo simulations. The results of our calcul ations are compared with the Kventsel-Luckhurst-Zewdie molecular field theo ry of smectogens, modified to include the effect of an external field. We h ave also used the simulations to explore the possibility of inducing more o rdered smectic phases with stronger fields. (C) 2000 American Institute of Physics. [S0021-9606(00)50509-1].