  We report Monte-Carlo simulation studies of some systems consisting of polar
rod-like molecules interacting via a pair potential that exhibit liquid crystal
phases, attributed with tilt angles of large magnitude. For theoretical
understanding of the microscopic origin of the tilted phases, different systems
consisting of prolate ellipsoidal molecules of three different lengths,
embedded with two symmetrically placed anti-parallel terminal dipoles are
considered. We find that the presence of a stable tilted phase crucially
depends on the molecular elongation which effectively makes dipolar separation
longer. We observe that in case of mesogens with transverse dipoles the tilt in
the layered smectic phase gradually increases from zero to a large magnitude as
we increase the molecular length. However tilt remains weak with molecular
elongation for systems with longitudinal dipoles which shows a small tilt at
shorter lengths. This is the first work determining the combined contribution
of dipolar separation and orientations in generating biaxial liquid crystal
phases with large tilt angles.
