Accurate Estimates of Infinite-Dilution Chemical Potentials of Small Hydrocarbons in Water via Molecular Dynamics Simulation
J T. Slusher
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.
Journal of Physical Chemistry B
Charging integral method, chemical potential, computer simulation, hydrocarbon, molecular dynamics, water
Accurate Estimates of Infinite-Dilution Chemical Potentials of Small Hydrocarbons in Water via Molecular Dynamics Simulation, Journal of Physical Chemistry B
(Accessed June 4, 2023)