Absolute hydration free energies

Lamoureux G, Roux B (2006) Absolute hydration free energy scale for alkali and halide ions established from simulations with a polarizable force field. J Phys Chem B 110(7) 3308-3322... 

Asthagiri, D. Pratt, L. R. Ashbaugh, H. S., Absolute hydration free energies ofions, ion-water clusters and quasichemical theory, J. Chem. Phys. 2003,119, 2702-2708... 

Ye M, Schuler RH (1986) The reaction of e aq with H2P04" as a source of hydrogen atoms for pulse radiolysis studies in neutral solutions. Radiat Phys Chem 28 223-228 Zhang C-G, Dixon DA (2003) The nature and absolute hydration free energy of the solvated electron in water. J Phys Chem B 107 4403-4417... 

G.-G. Zhan and D. A. Dixon, First-principles determination of the absolute hydration free energy of the hydroxide ion, J. Phys. Chem A, 106 (2002) 9737-9744. 

Figure 8.23 Comparison of experimental absolute hydration free energies for some monovalent ions with values calculated on the basis of the primitive quasi-chemical approximation, at ideal 1M standard state conditions (Asthagiri et al, 2003a), (a) with single-ion values shows an offset of positive and negative ions identifying at this level of approximation a potential of the phase contribution as discussed in Section 4.2, following p. 67. This offset vanishes with neutral combinations shown in (b).

Zhan, C.G., Dixon, D.A. Absolute hydration free energy of the proton from first-principles electronic structure calculations. J. Phys. Chem. A 2001,105(51), 11534M0. 

Qui et al. have compared experimental and calculated hydration free energies for a set of 35 small organic molecules with diverse functional groups by using the OPLS force field and the GB/SA hydration model [57], These calculations resulted in a mean absolute error of 0.9 kcal/mol. It is of interest to note that the results obtained with the GB/SA model were very similar to those obtained by the corresponding calculations using the full Poisson-Boltzmann equation. 

Blandamer and Symons (57) assumed in their work that the free energies of hydration of Rb+(g) and Cl (g) were identical, since the two ions have crystal radii of the same magnitude. Jain (58) has also applied the radii to calculate absolute free energies of ionic hydration. His treatment is in category (ii) and is based on the model developed by Frank and coworkers (59). The equation used is similar to that employed by Stokes (60) and utilizes calculated van der Waals radii of the ions as well as the crystal radii. To obtain the best agreement it was necessary to assume that the effective dielectric constant in water is 2.7. 

W. M. Latimer, K. S. Pitzer, and C. M. Slansky, J. Ghent. Phys., 7,108 (1939). Free Energy of Hydration of Gaseous Ions and the Absolute Potential of the Normal Calomel Electrode. 

Absolute values of free energies of hydration were made accessible by the work of Randles (7) who determined the absolute free energy of hydration of the K+ ion from measurements of Volta potentials. Since the absolute entropy of H+ is fairly well established (2), absolute values of enthalpy, free energy and entropy can be calculated for the hydration of ions. No comparable measmrements have been carried out in non-aqueous solvents. Application of extrapolation procedures to nonaqueous solvents is frequently restricted by the low solubility of salts in these solvents and lack of experimented data. 

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