High pressure studies on HOAB: Pressure dependence of the smectic C layer spacing

Abstract

Using an opposed diamond anvil cell, an X-ray investigation has been made of the pressure dependence of the layer spacing in the smectic C phase of 4,4'-bis(heptyloxy)azoxybenzene (HOAB) up to 3.8 kbar. It is found that the layer spacing is independent of pressure to within the experimental limits. It is concluded therefore that the suppression of the smectic C phase of this compound at higher pressures is not due to a tilt angle variation with pressure.