Accurate Estimates of Infinite-Dilution Chemical Potentials of Small Hydrocarbons in Water via Molecular Dynamics Simulation

Published

September 1, 1999

Author(s)

J T. Slusher

Abstract

The infinite dilution chemical potentials of methane, ethane, propane, benzene in water are precisely estimated using the single charging integral method [Chialvo, J. Chem. Phys. 1990, 92, 673; Chialvo, J. Phys. Chem. 1991, 95, 6683] in conjunction with molecular dynamics (MD) simulation using simple pair potentials. The method requires the calculation of ensemble averages of derivatives of the potential energy with respect to the model parameters. The derivatives take the form of pairwise energies which are easily obtained with minor modifications to an existing MD code. The present approach is found to be both stable and precise and allows individual contributions of the model parameters to the free energies to be determined. The dependence of the results for the benzene system on the size of the system is investigated, as is the sensitivity of all the results to the Lorentz-Berthelot combining rules. The importance of including long-ranged correlations in the results is highlighted. The computed chemical potentials for the united atom hydrocarbon models agree with experiment to within 0.7 kJ/mol.

Citation

Journal of Physical Chemistry B

Volume

103

Issue

No. 29

Pub Type

Journals

Keywords

Charging integral method, chemical potential, computer simulation, hydrocarbon, molecular dynamics, water

Citation

Slusher, J. (1999), Accurate Estimates of Infinite-Dilution Chemical Potentials of Small Hydrocarbons in Water via Molecular Dynamics Simulation, Journal of Physical Chemistry B (Accessed December 10, 2024)