Mean-field theory of anisotropic potential of rank L=4 and nonextensive formalism
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2004
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Abstract
In this study, we employ the potential Uij=-f(r ij)PL(cosθij) with rank L=4 to study on the nematic-isotropic phase transition, using generalized mean-field theory. We use a mean-field theory (P4 model) with this potential and generalize it using a nonextensive thermostatistics, namely Tsallis thermostatistics (TT). It is well known that mean-field theories have some insufficiencies. So we could expect similar insufficiencies from the P 4 model. Therefore to improve the P4 model, if necessary, one could use TT. In this study, we give the possible contributions of TT to the nematic-isotropic transition. TT includes a parameter which is called the entropy index and it is a measure of the nonextensivity of the system. In this framework, the variations of P̄4 and P̄2 vs. temperature have been showed for various values of the entropic index q. The entropy changes with respect to the entropic index have been also reported. © 2003 Elsevier B.V. All rights reserved.