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January 1, 1982Faraday Symposia of the Chemical Society255 citations

Thermodynamics of cavity formation in water. A molecular dynamics study

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JPJohan P. M. PostmaHBHerman J. C. BerendsenJHJ.R. Haak

Key Points

  • To determine the thermodynamics and free energy of cavity formation in water using molecular dynamics to model hydrophobic solute solvation.
  • Conducted six molecular dynamics simulations of liquid water containing repulsive cavities of varying sizes up to a 0.32 nm radius.
  • Applied perturbation statistical mechanics to compute Gibbs free energy as a function of cavity radius and analyzed water structuring around the cavities.
  • Calculated cavity formation free energy matched predictions from scaled-particle theory and predicted experimental surface tension to within 5%.
  • Determined radial distribution of water molecules across five cavity sizes, along with orientational and residence-time distributions for a 0.3 nm radius cavity.

Abstract

Thermodynamic quantities related to the solvation of hydrophobic solutes in water can be approximated by the application of scaled-particle theory. The crucial quantity is the Gibbs free energy of cavity formation. A series of six molecular-dynamics simulations of water including repulsive cavities of various sizes has been carried out. Using perturbation statistical mechanics, the free energy has been derived as a function of cavity radius up to 0.32 nm (0.32 nm approach of water oxygens to the cavity centre). The free energy agrees well with predictions from scaled-particle theory and the experimental surface tension is predicted to within 5%. The radial distribution of water molecules with respect to the cavity has been determined for five cavity sizes; for one size (radius of approach of water oxygens of 0.3 nm) the orientational distribution and the residence-time distribution in the hydration shells has been determined.

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Cite This Study

Postma et al. (1982) studied this question.

synapsesocial.com/papers/6a08ec5cafc616802fe4b90bhttps://doi.org/10.1039/fs9821700055
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