胆甾相液晶的相诱导双轴性

PHASE\|INDUCED BIAXIALITY IN CHOLESTERIC LIQUID CRYSTALS

采用胆甾相液晶的格胞理论，运用一定的统计方法，导出分布函数，定义序参数张量，由此推导出自由能表达式．在定域坐标系中，对胆甾相的长程取向序参数Ｓ和相诱导双轴序参数Δ进行了数值计算．所得的结果较前人有了不同程度的改善。

The liquid cell theory can be successfully applied to cholesteric liquid crystals. Using the statistical methods and defining an order parameter tensor, we deduce the distribution function and the Helmholtz free energy, which is the function of the order parameter tensor and its derivatives. The expression of the free energy we obtain has the same form with of the Landau theory. In a local coordinate system, the long\|range orientational parameter S and the phase\|induced biaxiality order parameter Δ are defined. By minimizing the Hemholtz free energy, we numerically calculate the temperature dependence of S and Δ .The results agree with the experiment.