Configurational temperature and local properties of the anisotropic Gay-Berne liquid crystal model: applications to the isotropic liquid/vapor interface and isotropic/nematic transition.
Résumé
Molecular simulations in the isothermal statistical ensembles require that the macroscopic thermal and mechanical equilibriums are respected and that the local values of these properties are constant at every point in the system. The thermal equilibrium in Monte Carlo simulations can be checked through the calculation of the configurational temperature, k(B)T(conf)=<|∇(r)U(r(N))|(2)>/<∇(r) (2)U(r(N))>, where ∇(r) is the nabla operator of position vector r. As far as we know, T(conf) was never calculated with the anisotropic Gay-Berne potential, whereas the calculation of T(conf) is much more widespread with more common potentials (Lennard Jones, electrostatic, ...). We establish here an operational expression of the macroscopic and local configurational temperatures, and we investigate locally the isotropic liquid phase, the liquid / vapor interface, and the isotropic-nematic transition by Monte Carlo simulations.