Raman scattering study of phase biaxiality in a thermotropic bent-core nematic liquid crystal

Phys Rev Lett. 2010 Jul 9;105(2):027801. doi: 10.1103/PhysRevLett.105.027801. Epub 2010 Jul 8.

Abstract

Polarized Raman spectroscopy was used to investigate the development of orientational order and the degree of phase biaxiality in a bent-core mesogenic system. The values of the uniaxial order parameters <P200> and <P400>, and biaxial order parameters <P220>, <P420>, and <P440>, and their evolution with temperature were determined. The temperature dependence of almost all order parameters reveals a second order transition from the uniaxial to biaxial nematic phase with <P220> increasing to ∼0.22 before a first order transition to the smectic-C phase, upon cooling.