ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Dense fluids of biaxial hard convex bodies exhibit a phase transition from an isotropic to a nematic (I–N) liquid–crystalline state. In the Onsager theory, the I–N transition is attributed to the tendency of pairs of molecules to minimize their excluded volume (or second virial coefficient, B2 ). In the present work, the mutual orientation dependence of B2 is calculated for hard biaxial ellipsoids and is expressed in a Wigner function expansion. Orientational distribution functions are determined for the Onsager model and for the Lee model, which incorporates some density correlations beyond those in the Onsager theory. In the uniaxial phase of biaxial molecules, the two nonzero order parameters calculated on the basis of hard-body models are in approximate accord with the findings of Maier–Saupe based theories. Introduction of biaxiality into a body has a pronounced effect: both the 〈P2〉 order parameter and the first orderness of the I–N transition are greatly reduced from that of comparable uniaxial bodies.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.460609
