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Title: Necessity of capillary modes in a minimal model of nanoscale hydrophobic solvation

Abstract

Modern theories of the hydrophobic effect highlight its dependence on length scale, emphasizing the importance of interfaces in the vicinity of sizable hydrophobes. We recently showed that a faithful treatment of such nanoscale interfaces requires careful attention to the statistics of capillary waves, with significant quantitative implications for the calculation of solvation thermodynamics. Here, we show that a coarse-grained lattice model like that of Chandler [Chandler D (2005) Nature 437(7059):640-647], when informed by this understanding, can capture a broad range of hydrophobic behaviors with striking accuracy. Specifically, we calculate probability distributions for microscopic density fluctuations that agree very well with results of atomistic simulations, even many SDs from the mean and even for probe volumes in highly heterogeneous environments. This accuracy is achieved without adjustment of free parameters, because the model is fully specified by well-known properties of liquid water. As examples of its utility, we compute the free-energy profile for a solute crossing the air-water interface, as well as the thermodynamic cost of evacuating the space between extended nanoscale surfaces. These calculations suggest that a highly reduced model for aqueous solvation can enable efficient multiscale modeling of spatial organization driven by hydrophobic and interfacial forces.

Authors:
 [1];  [2];  [3];  [3]
  1. Univ. of Chicago, IL (United States). Dept. of Chemistry
  2. Univ. of California, Berkeley, CA (United States). Biophysics Graduate Group
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Dept. of Chemistry
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR) (SC-21). Scientific Discovery through Advanced Computing (SciDAC)
OSTI Identifier:
1469127
Grant/Contract Number:  
AC02-05CH11231
Resource Type:
Accepted Manuscript
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 113; Journal Issue: 16; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Vaikuntanathan, Suriyanarayanan, Rotskoff, Grant, Hudson, Alexander, and Geissler, Phillip L. Necessity of capillary modes in a minimal model of nanoscale hydrophobic solvation. United States: N. p., 2016. Web. doi:10.1073/pnas.1513659113.
Vaikuntanathan, Suriyanarayanan, Rotskoff, Grant, Hudson, Alexander, & Geissler, Phillip L. Necessity of capillary modes in a minimal model of nanoscale hydrophobic solvation. United States. doi:10.1073/pnas.1513659113.
Vaikuntanathan, Suriyanarayanan, Rotskoff, Grant, Hudson, Alexander, and Geissler, Phillip L. Tue . "Necessity of capillary modes in a minimal model of nanoscale hydrophobic solvation". United States. doi:10.1073/pnas.1513659113. https://www.osti.gov/servlets/purl/1469127.
@article{osti_1469127,
title = {Necessity of capillary modes in a minimal model of nanoscale hydrophobic solvation},
author = {Vaikuntanathan, Suriyanarayanan and Rotskoff, Grant and Hudson, Alexander and Geissler, Phillip L.},
abstractNote = {Modern theories of the hydrophobic effect highlight its dependence on length scale, emphasizing the importance of interfaces in the vicinity of sizable hydrophobes. We recently showed that a faithful treatment of such nanoscale interfaces requires careful attention to the statistics of capillary waves, with significant quantitative implications for the calculation of solvation thermodynamics. Here, we show that a coarse-grained lattice model like that of Chandler [Chandler D (2005) Nature 437(7059):640-647], when informed by this understanding, can capture a broad range of hydrophobic behaviors with striking accuracy. Specifically, we calculate probability distributions for microscopic density fluctuations that agree very well with results of atomistic simulations, even many SDs from the mean and even for probe volumes in highly heterogeneous environments. This accuracy is achieved without adjustment of free parameters, because the model is fully specified by well-known properties of liquid water. As examples of its utility, we compute the free-energy profile for a solute crossing the air-water interface, as well as the thermodynamic cost of evacuating the space between extended nanoscale surfaces. These calculations suggest that a highly reduced model for aqueous solvation can enable efficient multiscale modeling of spatial organization driven by hydrophobic and interfacial forces.},
doi = {10.1073/pnas.1513659113},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
number = 16,
volume = 113,
place = {United States},
year = {2016},
month = {3}
}

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