Solvation ionic

The potential energy functions for both water and biomolecules are important in making atomistic simulations of biomolecules in solution quantitative. Water, as a liquid with many unique properties that are important for life on earth, must be modeled with 

McCammon, J. A., B. R. Gelin, and M. Karplus, Dynamics of folded proteins. Nature, 1977. 267 585-590. 

Salmon, J. P. Grossman, K. M. Mackenzie, J. A. Bank, C. Young, M. M. Deneroff, B. Batson, K. J. Bowers, E. Chow, M. P. Eastwood, D. J. lerardi, J. L. Klepeis, J. S. Kuskin, R. H. Larson, K. Lindorff-Larsen, P. Maragakis, M. A. Moraes, S. Piana, Y. Shan, and B. Towles, Millisecond-scale molecular dynamics simulations on Anton. Proc. Conf. High Perf. Comput. Network Storage Anal., 2009 1-11. 

Lindorff-Larsen, and D. E. Shaw, How robust are protein folding simulations with respect to force field parameterization Biophys.]., 2011.100 L47-L49. 

Klepeis, and D. E. Shaw, Assessing the accuracy of physical models used in protein-folding simulations quantitative assessment from long molecular dynamics simulations. Curr. Opin. Struct. Biol, 2014. 24 98-105. 10.1016/j.sbi.201312.066. 

---

Wood, R.H. Continuum electrostatics in a computational universe with finite cut-off radii and periodic boundary conditions Correction to computed free energies of ionic solvation. J. Chem. Phys. 103 (1995) 6177-6187. 

From the experimental results and theoretical approaches we learn that even the simplest interface investigated in electrochemistry is still a very complicated system. To describe the structure of this interface we have to tackle several difficulties. It is a many-component system. Between the components there are different kinds of interactions. Some of them have a long range while others are short ranged but very strong. In addition, if the solution side can be treated by using classical statistical mechanics the description of the metal side requires the use of quantum methods. The main feature of the experimental quantities, e.g., differential capacitance, is their nonlinear dependence on the polarization of the electrode. There are such sophisticated phenomena as ionic solvation and electrostriction invoked in the attempts of interpretation of this nonlinear behavior [2]. 

Padova, J. I. Ionic Solvation in Nonaqueous and Mixed Solvents 7... 

Ionic solvation is interaction between ions and solvent molecules that leads to the formation of relatively strong aggregates, the solvated ions. In aqueous solutions the terms ionic hydration and hydrated ions are used as weU. 

Thus, ionic solvation is associated with a substantial rearrangement of solvent structure its primary structure is broken where the ion is located, and its molecules undergo reorganization (reorientation) within a certain volume around the ion. 

For the electrolyte as a whole, the effects associated with cations and anions crossing the surface layer cancel, and Eq. (7.17) is valid, with both the chemical and the real ionic solvation energies. Next, we describe ways of theoretically calculating the solvation energies of individual ions or of calculating them from indirect experimental data. 

Equation (7.44) is known as the third approximation of the Debye-Hiickel theory. Numerous attempts have been made to interpret it theoretically, hi these attempts, either individual simplifying assumptions that had been made in deriving the equations are dropped or additional factors are included. The inclusion of ionic solvation proved to be the most important point. In concentrated solutions, solvation leads to binding of a significant fraction of the solvent molecules. Hence, certain parameters may change when solvation is taken into account since solvation diminishes the number of free solvent molecules (not bonded to the ions). The influence of these and some other factors was analyzed in 1948 by Robert A. Robinson and Robert H. Stokes. 

Stuart SJ, Berne BJ (1999) Surface Curvature Effects in the Aqueous Ionic Solvation of the Chloride Ion. J Phys Chem A 103(49) 10300-10307... 

Chang TM, Peterson KA, Dang LX (1995) Molecular-dynamics simulations of liquid, interface, and ionic solvation of polarizable carbon-tetrachloride. J Chem Phys 103(17) 7502-7513... 

Hunenberger, P. H. McCammon, J. A., Ewald artifacts in computer simulations of ionic solvation and ion-ion interactions a continuum electrostatics study, J. Chem. Phys. 1999,110, 1856-1872... 

Before considering different theoretical approaches to determining the free energies and other thermodynamic properties of ionic solvation, it is important to be aware of a problem on the experimental level. There are several methods available for obtaining these quantities for electrolyte solutions, both aqueous and nonaqueous some of these have been described by Conway and Bockris162 and by Padova.163 For example, enthalpies of solvation can be found via thermodynamic cycles, free energies from solubilities or galvanic cell potentials. However the results... 

Solvent reorganization can indeed be an important component of ionic solvation. For their aqueous solutions, Chandrasekhar et al. found that this required an energy input that was, in magnitude, from 25% to 50% of the ion-solvent attraction.173... 

A straightforward approach to ionic solvation, particularly for monatomic ions, is by means of the Bom equation,17 Eq. (32), which was introduced in Section III.2.i ... 

Techniques such as those described in Section III. 1, involving molecular dynamics or Monte Carlo simulations, have been used extensively to study ionic solvation. A classical... 

---