Near Critical Coexistence for an AUA Model of Thiophenes

Abstract

Near critical coexistence has been determined by means of parallel tempering coupled with grand canonical Monte Carlo simulations which were later recombined by using histogram reweighting techniques. The data collected during the simulations is not only useful to determine accurately the critical point but also to provide estimates for the coexistence density jump between the phases in equilibrium. A recently introduced algorithm by Kim [Kim Y.C. (2005) Phys. Rev. 71, 051501; Kim Y.C. (2005) Comput. Phys. Commun. 169, 295], based on the scaling of the positions of the different minima found for the Binder parameter, has been applied to the case of a realistic model of thiophene consisting of different Lennard Jones sites. Contrary to the case of the Hard Core Square Well (HCSW) and Restricted Primitive Model (RPM) systems, significant corrections to scaling are found in this case. By readapting the algorithm we are able to calculate the coexistence in the critical region.