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Physical origin underlying the entropy loss upon hydrophobic hydration
1National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia. aljaz.godec@ki.si
Journal of the American Chemical Society
|September 26, 2012
Summary
The hydrophobic effect is not caused by water ordering around particles. Instead, it arises from many-body correlations in water
Area of Science:
- Physical Chemistry
- Biophysics
- Computational Chemistry
Background:
- The hydrophobic effect (HE) drives biomolecular assembly in water.
- Traditionally, HE is attributed to water ordering and entropic origins.
- Existing models focus on average water structure and pairwise correlations.
Purpose of the Study:
- To challenge the traditional view of the hydrophobic effect.
- To present a new molecular-level understanding of HE.
- To investigate the role of collective fluctuations and many-body correlations in HE.
Main Methods:
- Computer simulations of water-solute interactions.
- Analysis of collective fluctuations in water clusters.
- Examination of many-body correlations beyond pairwise interactions.
Main Results:
- The traditional picture of HE based on average water structure is incorrect.
- HE is driven by many-body correlations affecting hydrogen bond switching.
- These correlations involve nonlocal compensation of electrostatic field fluctuations.
Conclusions:
- A new model for HE based on maximizing electrostatic noise is proposed.
- This noise arises from nonlocal fluctuations in the hydrogen bond network.
- Strong correlations among at least four water molecules are key to HE.
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