Calculation of the free energy of solvation from molecular dynamics
simulations
P. F. B. Gon�alves and H. Stassen
Grupo de Química Teórica, Instituto
de Química, Universidade Federal do Rio
Grande do Sul, 91540-000 Porto Alegre-RS, Brazil
Abstract:
Molecular dynamics simulation has been employed in the computation
of the free energy of solvation for a large number of solute molecules
with different chemical functionalities in the solvents water, acetonitril,
dimethyl sulfoxide, tetrahydrofuran, and carbon disulfide. The free
solvation energy has been separated into three contributions: the work
necessary to create a cavity around the solute in the solvent, the electrostatic
contribution, and the free energy containing the short-range interactions
between solute and solvent molecules. The cavitational contribution
was computed from the Claverie-Pierotti model applied to excluded volumes
obtained from nearest-neighbor solute-solvent configurations treating
the solvent molecules as spherical. The electrostatic term was calculated
from a dielectric continuum approach with explicitly incorporating the
solvent's partial charges. The short-range contribution to the free
solvation energy was obtained from the force field employed in the simulations.
For solutions with available experimental data for the free energy of
solvation, we found a satisfactory agreement of the computed free solvation
energies and the experimental data set.
*Lecture presented at the European Molecular Liquids
Group (EMLG) Annual Meeting on the Physical Chemistry of Liquids: Novel
Approaches to the Structure, Dynamics of Liquids: Experiments, Theories,
and Simulation,Rhodes, Greece, 7-15 September 2002. Other presentations
are published in this issue, pp. 1-261.
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