Properties of polar Gay-Berne particles in cubic and tetragonal simulationboxes

Molecular dynamics simulations for molecules represented by the Gay-Berne e llipsoidal particles with non-central transverse and longitudinal dipole mo ments are reported. The system is compressed at constant temperature and th e highest density corresponds to the tightest packing of hard ellipsoids. T he thermodynamic and structural properties obtained from simulations for th e cubic and tetragonal simulation cells are compared. In general, the isotr opic-smectic phase transition is independent of the simulation box shape. F or the molecules with axial dipoles an additional transition is observed in the orientationally ordered phase. It seems that the second transition is connected with the periodic boundary conditions and tilt of molecular layer s with respect to the simulation box. (C) 2000 Elsevier Science B.V. All ri ghts reserved.