Role of Solute Attractive Forces in the Atomic-Scale Theory of Hydrophobic Effects

Journal Article · Wed May 16 00:00:00 EDT 2018 · Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry

DOI:https://doi.org/10.1021/acs.jpcb.8b01711· OSTI ID:1474051

Gao, Ang ^[1]; Tan, Liang ^[2]; Chaudhari, Mangesh I.  ^[3]; Asthagiri, D.  ^[4]; Pratt, Lawrence R.  ^[2]; Rempe, Susan B.  ^[3]; Weeks, John D.  ^[1]

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1. Univ. of Maryland, College Park, MD (United States). Inst. for Physical Science and Technology, and Dept. of Chemistry and Biochemistry
2. Tulane Univ., New Orleans, LA (United States). Dept. of Chemical and Biomolecular Engineering
3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Center for Biological and Engineering Sciences
4. Rice Univ., Houston, TX (United States). Chemical and Biomolecular Engineering

The role that van der Waals (vdW) attractive forces play in the hydration and association of atomic hydrophobic solutes such as argon (Ar) in water is reanalyzed using the local molecular field (LMF) theory of those interactions. In this problem, solute vdW attractive forces can reduce or mask hydrophobic interactions as measured by contact peak heights of the ArAr correlation function compared to reference results for purely repulsive core solutes. Nevertheless, both systems exhibit a characteristic hydrophobic inverse temperature behavior in which hydrophobic association becomes stronger with increasing temperature through a moderate temperature range. The new theoretical approximation obtained here is remarkably simple and faithful to the statistical mechanical LMF assessment of the necessary force balance. In conclusion, our results extend and significantly revise approximations made in a recent application of the LMF approach to this problem and, unexpectedly, support a theory of nearly 40 years ago.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1474051
• Report Number(s): SAND-2018-10155J; 667918
• Journal Information: Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry, Vol. 122, Issue 23; ISSN 1520-6106
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

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