Vapor-liquid equilibria and thermophysical behavior of the SPC-HW model for heavy water

A. A. Chialvo, J. Horita

Research output: Contribution to journalArticlepeer-review

Abstract

The vapor-liquid coexistence curve of the simple point charge heavy-water model (SPC-HW), [ J. Chem. Phys. , 114 , 8064-8067 (2001)] is determined by Gibbs Ensemble Monte-Carlo (GEMC) simulation. The estimated critical conditions of the model based on the Wegner-type expansion for the order parameters and the rectilinear diameter are c = 0.300 g/cc, T c = 661 K and P c = 156 bars. The dielectric constant determined by isothermal-isochoric molecular dynamics is underpredicted along the coexistence curve by 29-44% in comparison with the experimental values. The analysis of the orthobaric temperature dependence of the system microstructure, in terms of the three site-site radial distribution functions, indicates that the first coordination numbers for the oxygen-oxygen and the oxygen-deuterium interactions are 4.3 0.1 and 1.9 0.1 at T = 300 K, and decrease by 15 and 55%, respectively, at criticality. The dipole-dipole correlation functions show that the orientational order in heavy water is quickly lost beyond the first oxygen-oxygen coordination shell. The model's second virial coefficient is determined by Monte-Carlo integration and used to aid the interpretation of the predicted phase equilibrium results.

Original languageEnglish
Pages (from-to)1035-1042
Number of pages8
JournalMolecular Simulation
Volume31
Issue number14-15
DOIs
StatePublished - Dec 1 2005

Keywords

  • Gibbs Ensemble Monte-Carlo
  • Heavy water
  • SPC-HW model
  • Second virial coefficient
  • Vapor-liquid equilibria

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