Theory of melting of molecular crystals III: the effect of short range orientational order on liquid crystalline transitions

Chandrasekhar, S. ; Shashidhar, R. (1972) Theory of melting of molecular crystals III: the effect of short range orientational order on liquid crystalline transitions Molecular Crystals and Liquid Crystals, 16 . pp. 21-32. ISSN 1058-725X

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Related URL: http://dx.doi.org/10.1080/15421407208083576

Abstract

The theory of melting of molecular crystals developed in Parts I and II is extended to include short range orientational order. The thermodynamic properties are evaluated by the quasi-chemical method, which is mathematically equivalent to Bethe's treatment, and the theory is applied to liquid crystalline transitions. The interesting result is obtained that the nematic-isotropic transition is always first order, and that although the long range orientational order disappears suddenly at this transition point, a certain degree of short range orientational order persists in the isotropic phase. The specific heat exhibits both pre- and post-transition anomalies, in conformity with observations. The thermal expansion and isothermal compressibility show pre-transition anomalies but, contrary to experimental facts, no post-transition anomalies, indicating that even the quasi-chemical approach is not quite adequate for explaining all the properties.

Item Type:Article
Source:Copyright of this article belongs to Taylor and Francis Ltd.
ID Code:7834
Deposited On:25 Oct 2010 10:13
Last Modified:16 May 2016 17:57

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