Theory of nine elastic constants of biaxial nematics

• 来源期刊: 中国物理B（英文版）
• 关键词: biaxial nematic liquid crystal elastic theory
• 年，卷（期）: 2008,（3）
• 页码范围: 1060-1069
• 页数: 10页
• 语种: 英文

摘要

In this paper, a rotational invariant of interaction energy between two biaxial-shaped molecules is assumed and in the mean field approximation, nine elastic constants for simple distortion patterns in biaxial nematica are derived in terms of the thermal average<D(l)mn><D(l')m'n'>where D(l)mn is the Wigner rotation matrix.In the lowest order terms, the elastic constants depend on coefficients г,г',λ, order parameters Q0=Q0<D(2)00>+Q2<D(2)02+D(2)0-2>vj'j''j(r12) and probability function fk'k'' k (r12), where r12 is the distance between two molecules, andλis proportional to temperature. Q0 and Q2 are parameters related to multiple moments of molecules. Comparing these results with those obtained from Landau-de Gennes theory, we have obtained relationships between coefficients, order parameters used in both theories. In the special case of uniaxial nematics, both results are reduced to a degenerate case where K11=K33.