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Register a new userLiquid-Vapor Transition and Critical Behavior of The Ultrasoft Restricted Primitive Model of Polyelectrolytes : a Monte Carlo Study
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Jean-Michel Caillol
Publication date
2014
fields
Physics
and research's language is
English
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We present a Monte-Carlo study of the liquid-vapor transition and the critical behavior of a model of polyelectrolytes with soft gaussian charge distributions introduced recently by Coslovich, Hansen, and Kahl [J. Chem. Phys. textbf{134}, 244514 (2011)]. A finite size study involving four different volumes in the grand canonical ensemble yields a precise determination of the critical temperature, chemical potential, and density of the model. Attempts to determine the nature of the criticality and to obtain reliable values for the critical exponents are not conclusive.
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Reassessment of the critical temperature and density of the restricted primitive model of an ionic fluid by Monte Carlo simulations performed for system sizes with linear dimension up to $L/sigma=34$ and sampling of $sim 10^9$ trial moves leads to $T^*_c=0.04917 pm 0.00002$ and $rho_c^* =0.080 pm 0.005$. Finite size scaling analysis based in the Bruce-Wilding procedure gives critical exponents in agreement with those of the 3d Ising universality class. An analysis similar to that proposed by Orkoulas et al [Phys. Rev. E 63, 051507 (2001)], not relying on an a priori knowledge of the universality class, leads to an unaccurate estimate of $T_c^*$ and to unexpected behavior of the specific heat and value of the critical exponent ratio $gamma/ u$.
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