Free energy in solutions

Schaefer M, van Vlijmen HWT, Karplus M (1998) Electrostatic contributions to molecular free energies in solution. Adv Protein Chem 51 1-57. 

Continuum models have a long and honorable tradition in solvation modeling they ultimately have their roots in the classical formulas of Mossotti (1850), Clausius (1879), Lorentz (1880), and Lorenz (1881), based on the polarization fields in condensed media [32, 57], Chemical thermodynamics is based on free energies [58], and the modem theory of free energies in solution is traceable to Bom s derivation (1920) of the electrostatic free energy of insertion of a monatomic ion in a continuum dielectric [59], and Kirkwood and Onsager s... 

Excess Free Energies in Solutions of Isotopes Connections Between VPIE, the Liquid Vapor Fractionation Factor, a, and RPFR... 

The trajectory is then post-processed to determine absolute free energies in solution for biotin, avidin, and the avidin-biotin complex. This process begins by stripping the water from the trajectory, and then computing absolute free energy as... 

First and Second Derivatives of the Free Energy in Solution... 

In most cases, and particularly for medium to high polarity solvents, the electrostatic interactions provide the largest contribution to the free energy in solution as a consequence, this contribution to first and second energy derivatives in solution is also the most important and significant. If the self-consistent field (SCF) energy in the gas phase... 

We assessed the stability of loops by evaluating their relative conformational free energy compared with CDRs from Fv R45. The conformational free energy in solution can be described in terms of a thermodynamic cycle and equation 1. 

The full calculation of the ligand-protein interaction free energy in solution, as diagrammed in Fig. 10b, corresponds to the determination of the free energy of solvation of the three separate species and the evaluation of the appropriate difference i.e.,... 

The nature of the 1 1 inclusion complexes of 3 with the fluoride or chloride ion in water were described and compared with the X-ray structure of the relevant compound. Furthermore, simulations involving the uncomplexed ligand and both anions led to the experimentally observed over Cn binding selectivity, which was reproduced quantitatively by free-energy perturbation (FEP) calculations.The latter provide a thermodynamic measure of the relative interaction and binding free energies in solution, these are, of course, of particular interest in supramolecular chemistry, where molecular association is of paramount importance. 

Consider a generic excited electronic state (2) together with the corresponding ground state (1). As discussed by Improta et al. [86], in SS methods the excited-state equilibrium [ eq(2)] free energy in solution thus explicitly depends on the excited... 

Sometimes one is given the free energy of a compound in the solid form and desires its free energy in solution. In order to calculate this quantity one uses the fact that F of the substance in saturated solution is the same as that of the solid because the phases are in equilibrium so by use of the solubility plus equation 3 to determine AF of dilution one calculates F in a solution of the desired concentration. ... 

As mentioned above, (partial) cancelation of errors calculated for relative free energies in solution is also possible. Nevertheless, some studies have pointed out [13, 14] that the solute-solvent relative solvation free energy can differ by up to 1-2 kcal mol as determined on the basis of some continuum and explicit solvent methods. This uncertainty is very large when an equilibrium constant smaller than about 10 is to be determined. 

---