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11:03
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Soft collective fluctuations governing hydrophobic association
Aljaž Godec1, Jeremy C Smith, Franci Merzel
1National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia and Institute for Physics and Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany.
Physical Review Letters
|October 8, 2013
Summary
Hydrophobic interactions are driven by collective water fluctuations, not just entropy. These fluctuations, involving hydrogen bonds, dictate the kinetics and microscopic details of particle association in water.
Area of Science:
- Physical Chemistry
- Computational Chemistry
- Biophysics
Background:
- Traditional hydrophobic interaction (HI) models focus on water entropy release.
- These models fail to explain the kinetics and microscopic mechanisms of HI.
Purpose of the Study:
- To elucidate the microscopic picture of hydrophobic interactions.
- To identify the key factors governing the kinetics of hydrophobic association.
Main Methods:
- Monte Carlo simulations of apolar solutes in aqueous solution.
- Analysis of collective fluctuations in the hydrogen bond (HB) network.
- Investigation of solute-water translational correlations.
Main Results:
- Collective fluctuations in the HB network are crucial for HI.
- Relaxation of solute-water translational correlations is a primary contributor to HI.
- A heat capacity maximum is linked to softening of water fluctuations and HB network correlations.
- Large collective fluctuations in hydration water drive hydrophobic association kinetics.
Conclusions:
- Hydrophobic interaction is fundamentally governed by collective water dynamics and HB network rearrangements.
- The kinetics of association are dictated by critical collective fluctuations in the hydration shell.
- A new microscopic understanding of HI emerges, emphasizing water's dynamic role.
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