Free energy, entropy, and internal energy of hydrophobic interactions: Computer simulations

Smith, David E.; Haymet, A. D. J.
April 1993
Journal of Chemical Physics;4/15/1993, Vol. 98 Issue 8, p6445
Academic Journal
Hydrophobic interactions are investigated by molecular dynamics computer simulations of the free energy, entropy, and internal energy of association of two methane molecules in water. Recently we reported a computer simulation calculation of the entropy of association of methane in water [J. Am. Chem. Soc. 114, 5875 (1992)], where entropy drives nonpolar solutes together at short distances. Here this method is compared with two other general methods for the calculation of the entropic contribution to the free energy. The calculated thermodynamic quantities for methane association are in good agreement with available experimental measurements. Solute contact configurations are found to be of greater importance than solvent-separated configurations, in conflict with earlier theoretical and simulation studies of similar systems. In some cases, this conflict may be understood in terms of differences in the assumed, model intermolecular potential energies.


Related Articles

  • Environmental swap energy and role of configurational entropy in transfer of small molecules from water into alkanes. Smejtek, Pavel; Word, Robert C. // Journal of Chemical Physics;1/15/2004, Vol. 120 Issue 3, p1383 

    We studied the effect of segmented solvent molecules on the free energy of transfer of small molecules from water into alkanes (hexane, heptane, octane, decane, dodecane, tetradecane, and hexadecane). For these alkanes we measured partition coefficients of benzene, 3-methylindole (3MI),...

  • Atomistic simulations of the solubilization of single-walled carbon nanotubes in toluene. Grujicic, M.; Cao, G.; Roy, W.N. // Journal of Materials Science;Apr2004, Vol. 39 Issue 7, p2315 

    Solubilization of the armchair, metallic (10,10) single-walled carbon nanotubes (SWCNTs) in toluene is modeled using molecular dynamics simulations. Inter- and intra-molecular atomic interactions in the SWCNT + toluene system are represented using COMPASS (Condensed-phased Optimized Molecular...

  • Efficient multidimensional free energy calculations for ab initio molecular dynamics using classical bias potentials. VandeVondele, Joost; Rothlisberger, Ursula // Journal of Chemical Physics;9/22/2000, Vol. 113 Issue 12 

    We present a method for calculating multidimensional free energy surfaces within the limited time scale of a first-principles molecular dynamics scheme. The sampling efficiency is enhanced using selected terms of a classical force field as a bias potential. This simple procedure yields a very...

  • Energetic teaching: The intimate relationship between... Macfarlane, Jeff J. // Journal of Biological Education (Society of Biology);Winter92, Vol. 26 Issue 4, p295 

    Discusses the use of Gibbs free energy in biology in understanding energetics. Discussion of the concept of Gibbs free energy in terms of entropy; Need for students to understand the importance of learning about energetics.

  • Hydrophobic interactions between methane and a nanoscopic pocket: Three dimensional distribution of potential of mean force revealed by computer simulations. Setny, Piotr // Journal of Chemical Physics;3/28/2008, Vol. 128 Issue 12, p125105 

    We consider a model system of methane molecule and a hemispherical, hydrophobic pocket of an 8 Ã… radius, remaining together in aqueous environment. A spatial map of potential of mean force acting on methane molecule due to presence of pocket is constructed, based on a series of explicit...

  • Statistical mechanical expression of entropy production for an open quantum system. Majima, Hiroki; Suzuki, Akira // AIP Conference Proceedings;Feb2013, Vol. 1518 Issue 1, p714 

    A quantum statistical expression for the entropy of a nonequilibrium system is defined so as to be consistent with Gibbs' relation, and is shown to corresponds to dynamical variable by introducing analogous to the Heisenberg picture in quantum mechanics. The general relation between...

  • Free energy calculation of water addition coupled to reduction of aqueous RuO4-. Tateyama, Yoshitaka; Blumberger, Jochen; Ohno, Takahisa; Sprik, Michiel // Journal of Chemical Physics;5/28/2007, Vol. 126 Issue 20, p204506 

    Free energy calculations were carried out for water addition coupled reduction of aqueous ruthenate, RuO4-+H2O+e-→[RuO3(OH)2]2-, using Car-Parrinello molecular dynamics simulations. The full reaction is divided into the reduction of the tetrahedral monoanion, RuO4-+e-→RuO42-,...

  • Entropy of single-file water in (6,6) carbon nanotubes. Waghe, Aparna; Rasaiah, Jayendran C.; Hummer, Gerhard // Journal of Chemical Physics;7/28/2012, Vol. 137 Issue 4, p044709 

    We used molecular dynamics simulations to investigate the thermodynamics of filling of a (6,6) open carbon nanotube (diameter D = 0.806 nm) solvated in TIP3P water over a temperature range from 280 K to 320 K at atmospheric pressure. In simulations of tubes with slightly weakened carbon-water...

  • Determination of free energy of the crystal-melt interface. Pisarev, V. // High Temperature;Nov2012, Vol. 50 Issue 6, p717 

    The results of calculation of the free energy γ of the crystal-melt interface using the molecular dynamics method are presented. The interfacial energy is determined from analysis of the capillary fluctuations spectrum in the two-phase system. The free energy values of the crystal-melt...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics