Srivastava A, Sa D, Singh S
Department of Physics, Banaras Hindu University, Varanasi-221005, India.
Eur Phys J E Soft Matter. 2006 May;20(1):63-9. doi: 10.1140/epje/i2005-10121-8. Epub 2006 May 8.
Within the framework of Landau-de-Gennes formulation, we analyse the effect of pressure on electric-field-induced phase transitions in a liquid crystal which shows spontaneously an isotropic-smectic A transition. Inferring from the experimental pressure dependences on the layer spacing in smectic A phase, as well as the nematic-smectic A metastable temperature T*(AN), we incorporated the pressure dependence in the free energy through (the surface energy term) and the coupling between the quadrupolar nematic ordering Q(ij) and the smectic order parameter psi. From the S-T phase diagram, we found that the stability of field-induced nematic phase increases with pressure, whereas the discontinuity of the transition decreases. Also, the region where paranematic phase transits directly to smectic A phase increases with pressure.
在朗道 - 德热纳理论框架内，我们分析了压力对一种液晶中电场诱导相变的影响，该液晶自发呈现各向同性 - 近晶A相变。从实验得到的压力对近晶A相层间距以及向列相 - 近晶A亚稳温度T*(AN)的依赖关系推断，我们通过（表面能项）以及四极向列序Q(ij)与近晶序参量ψ之间的耦合，将压力依赖性纳入自由能中。从S - T相图中，我们发现场诱导向列相的稳定性随压力增加，而相变的不连续性减小。此外，顺排相直接转变为近晶A相的区域也随压力增加。
