Monte Carlo simulations and integral equation theory for microscopic correlations in polymeric fluids

Yethiraj, Arun; Hall, Carol K.
January 1992
Journal of Chemical Physics;1/1/1992, Vol. 96 Issue 1, p797
Academic Journal
Monte Carlo simulations are performed for polymer chains modeled as pearl necklaces of freely jointed tangent hard spheres; chains composed of 20, 50, and 100 beads are studied at volume fractions ranging from 0.1 to 0.35. The mean-square end-to-end distance, the radius of gyration, and the intramolecular and intermolecular site–site distribution functions are monitored in the simulations. Various approximations for the intramolecular structure factor, w(k), are tested. It is found that the w(k) from the semi-flexible chain model is the most accurate. The polymer ‘‘reference interaction site model’’ (PRISM) theory of Curro and Schweizer is tested using both approximate and exact expressions for w(k). It is found that, at the densities examined here, the theory is accurate for the local structure except near contact where it tends to overestimate the value of the intermolecular site–site distribution function, g(r). The polymer-RISM theory is also solved with the generalized mean spherical approximation (GMSA), which uses a Yukawa closure for the direct correlation function. The contact value of g(r), required in the GMSA, is obtained approximately, but accurately, via a perturbation expansion for a hypothetical fluid and the generalized Flory dimer equation of state. The GMSA theory results in improved predictions for g(r) when compared with the original polymer-RISM theory, but there are still some differences between theoretical predictions and simulation results near contact.


Related Articles

  • Orientation-dependent integral equation theory for a two-dimensional model of water. Urbicˇ, T.; Vlachy, V.; Kalyuzhnyi, Yu. V.; Dill, K. A. // Journal of Chemical Physics;3/22/2003, Vol. 118 Issue 12, p5516 

    We develop an integral equation theory that applies to strongly associating orientation-dependent liquids, such as water. In an earlier treatment, we developed a Wertheim integral equation theory (IET) that we tested against NPT Monte Carlo simulations of the two-dimensional Mercedes Benz model...

  • Hard-sphere fluids inside spherical, hard pores. Grand canonical ensemble Monte Carlo calculations and integral equation approximations. Sloth, Peter // Journal of Chemical Physics;7/15/1990, Vol. 93 Issue 2, p1292 

    Density profiles and partition coefficients are obtained for hard-sphere fluids inside hard, spherical pores of different sizes by grand canonical ensemble Monte Carlo calculations. The Monte Carlo results are compared to the results obtained by application of different kinds of integral...

  • Integral equation study of parallel hard spherocylinders. Caillol, J. M.; Weis, J. J. // Journal of Chemical Physics;6/15/1989, Vol. 90 Issue 12, p7403 

    The hypernetted chain (HNC) and Percus–Yevick (PY) integral equations are solved numerically for parallel hard spherocylinders of length-to-width ratios L/σ ranging from 0.5 to 5.0. The PY virial pressure is in excellent agreement with Monte Carlo data. The HNC equation gives evidence...

  • Background and bridge functions for the homonuclear hard diatomic fluid. Lomba, E.; Lombardero, M.; Abascal, J. L. F. // Journal of Chemical Physics;6/15/1989, Vol. 90 Issue 12, p7330 

    The Monte Carlo method has been used to compute the coefficients of the spherical harmonic expansion of the function y=g exp(βu) for a hard diatomic fluid. The ‘‘series’’ function S(12) is also computed from MC data by means of an integral equation procedure. Thus,...

  • Colloidal interactions mediated via polyelectrolytes. Podgornik, Rudolf; Åkesson, Torbjörn; Jönsson, Bo // Journal of Chemical Physics;6/15/1995, Vol. 102 Issue 23, p9423 

    Using Monte Carlo simulation, scaling, variational and mean-field arguments we investigate forces between charged spherical aggregates conferred by oppositely charged polymeric chains. Two types of polymer mediated attraction are found in this system, both of a bridging type but differing...

  • Grand canonical Monte Carlo and modified singlet integral equations for the density profile of a... Olivares-Rivas, Wilmer; Degreve, Leo // Journal of Chemical Physics;5/15/1997, Vol. 106 Issue 19, p8160 

    Describes the grand canonical Monte Carlo and modified singlet interval equations for the density profile of a Yukawa fluid near a planar wall. Application of the integral equations to the Yukawa fluid of diameter sigma near a hard wall.

  • Fused hard-sphere chain molecules: Comparison between Monte Carlo simulation for the bulk pressure and generalized Flory theories. Costa, Lorenza A.; Zhou, Yaoqi; Hall, Carol K.; Carrà, Sergio // Journal of Chemical Physics;4/15/1995, Vol. 102 Issue 15, p6212 

    We report Monte Carlo simulation results for the bulk pressure of fused-hard-sphere (FHS) chain fluids with bond-length-to-bead-diameter ratios ≊ 0.4 at chain lengths n=4, 8 and 16. We also report density profiles for FHS chain fluids at a hard wall. The results for the compressibility...

  • A comparison of density functional and integral equation theories vs Monte Carlo simulations for.... Segura, Chad J.; Vakarin, Eduard V. // Journal of Chemical Physics;3/22/1998, Vol. 108 Issue 12, p4837 

    Compares the perturbation density functional (DF) and integral equation (IE) theories with the Monte Carlo simulations for hard sphere associating fluids. Description of the DF and IE theories; Profiles of monomers for the DF theory; Factors affecting the accuracy of DF and IE theories.

  • A two-dimensional model of water: Solvation of nonpolar solutes. Urbicˇ, T.; Vlachy, V.; Kalyuzhnyi, Yu. V.; Southall, N. T.; Dill, K. A. // Journal of Chemical Physics;1/8/2002, Vol. 116 Issue 2, p723 

    We recently applied a Wertheim integral equation theory (IET) and a thermodynamic perturbation theory (TPT) to the Mercedes–Benz (MB) model of pure water. These analytical theories offer the advantage of being computationally less intensive than the Monte Carlo simulations by orders of...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics