Effect of electrostatic interaction

Fig. 2.16 Effect of electrostatic interactions on 3i4-helix formation in an aqueous environment [1 75 a, 175 b, 176]. y -Peptides 86 and 87 adopt a stable helical conformation mediated by salt bridges near neutral pH. While the propensity of these peptides to adopt a helical conformation is strongly de-...

M Ilavsky. Effect of electrostatic interactions on phase transition in the swollen polymeric network. Polymer 22 1687-1697, 1981. 

In fact this "unhydrolyzed" polyacrylamide sample is slightly charged and its low polyectrolyte character is confirmed by a slight difference of red values at pH 7 and 5, for salt free solutions. A really neutral polymer should be necessary to differentiate low effects of electrostatic interactions from non ionic interactions. coordination binding at low pH and hydrogen bonds at pH 7. Nevertheless, at this pH, the adsorption of the chain on Al(0H)3 aggregates can probably be considered as the main origin of the loss of viscosity. 

Quiquampoix H (1987) A stepwise approach to the understanding of extracellular enzyme activity in soil. I. Effect of electrostatic interactions on the conformation of a P-D-glucosidase adsorbed on different mineral surfaces. Biochimie 69 753-763... 

In the virial methods, therefore, the activity coefficients account implicitly for the reduction in the free ion s activity due to the formation of whatever ion pairs and complex species are not included in the formulation. As such, they describe not only the factors traditionally accounted for by activity coefficient models, such as the effects of electrostatic interaction and ion hydration, but also the distribution of species in solution. There is no provision in the method for separating the traditional part of the coefficients from the portion attributable to speciation. For this reason, the coefficients differ (even in the absence of error) in meaning and value from activity coefficients given by other methods. It might be more accurate and less confusing to refer to the virial methods as activity models rather than as activity coefficient models. 

Effect of Electrostatic Interactions on the Bimolecular Rate Constant. The bimolecular rate equation presented above does not account for the effect of electrostatic interactions on reactivity of ionic molecules. Brpnsted and Bjerrum, among others, recognized that the behavior... 

Other modifications to the theory of Anderson and Quinn [142] have been reviewed by Deen [146]. Malone and Quinn [147] modified the above theory to include the effect of electrostatic interactions on transport in microporous membranes. Smith and Deen [148] have also looked at these electrostatic or double layer interactions. More recently, Kim and Anderson [149] investigated the hindrance of solute transport in polymer lined micropores. Also, as briefly mentioned above, an excellent review of the theories presented for transport in microporous membranes has been given by Deen [146]. 

Veerman, C., Ruis., H., Sagis, L.M.C., van der Linden E. (2002). Effect of electrostatic interactions on the percolation concentration of fibrillar P-lactoglobulin gels. Biomacromolecules, 3, 869-873. 

In our first paper [34] in this field, we presented a theory which described the effect of electrostatic interactions of charges on the chain on the collapse. 

Table 7.2 shows these predictions to be home out by a large number of reactions, but there are exceptions where the A factors are much lower than expected. These can be explained if the internal degrees of freedom are considered. Effects of electrostatic interactions and of solvation are small, and could be in either direction, but the dominant effect is probably due to internal motions. 

The model of a dipole in a spherical cavity can only provide qualitative insights into the behaviour of real molecules moreover, it cannot explain the effect of electrostatic interactions in the case of apolar molecules. More accurate predictions require a more detailed representation of the molecular charge distribution and of the cavity shape this is enabled by the theoretical and computational tools nowadays available. In the following, the application of these tools to anisotropic liquids will be presented. First, the theoretical background will be briefly recalled, stressing those issues which are peculiar to anisotropic fluids. Since most of the developments for liquid crystals have been worked out in the classical context, explicit reference to classical methods will be made however, translation into the quantum mechanical framework can easily be performed. Then, the main results obtained for nematics will be summarized, with some illustrative... 

Effects of electrostatic interactions on orientational order of solutes in liquid crystals, A. di Matteo, A. Ferrarini and G. J. Moro, J. Phys. Chem. B, 104, (2000) 7764-7773. 

The basic point is that the mass action laws of chemistry ([A][B]/[AB] = constant) do not work for ions in solution. The reason they do not work puzzled ehemists for 40 years before an acceptable theory was found. The answer is based on the effects of electrostatic interaction forces between the ions. The mass aetion laws (in terms of concentrations) work when there are no charges on the partieles and hence no long-range attraction between them. When the particles are charged. Coulomb s law applies and attractive and repulsive forces (dependent on 1/r where r is the distanee between the ions) come in. Now the particles are no longer independent but puU on each other and this impairs the mass action law, the silent assumption of which is that ions are free to act alone. 

The structures of the pairs have been determined by ab initio calculations. Surprisingly, while the absorption spectrum of the solvated electron presents a single band located around 2250 nm, the absorption spectra of the pairs are blue-shifted and composed of two bands (Fig. 7)7 Those spectra were interpreted as a perturbation of the solvated electron spectrum with the use of an asymptotic model. This model describes the solvated electron as a single electron trapped in a THF solvent cavity and takes into account the effects of electrostatic interaction and polarization due to the solutes that are modeled by their charge distribution. It was shown that the p-like excited states of the solvated electron can be split in the presence of molecules presenting a dipole. So, the model accounts for the results obtained with dissociated alkali and non-dissociated alkaline earth salts in THF since ionic solutes yield absorption spectra with only one absorption band, and dipolar neutral solutes yield absorption spectra with two bands (Fig. 8). ... 

Singh MP, Lumpkin JA, and Rosenblatt J. Effect of electrostatic interactions on polylysine release rates from collagen matrices and comparison with model predictions. J. Control Rel. 1995 35 165-179. 

Fujii, G. To fuse or not to fuse the effect of electrostatic interactions, hydrophobic forces and structural amphilicity on protein-mediated membrane destabilization. Adv. Drug Deliv. Rew. 1999, 38, 257-277. 

Yokoyama, A., Srinivasan, K. R., and Fogler, H. S. (1988) Stabilization Mechanism by Acidic Polysaccharides. Effects of Electrostatic Interactions on Stability and Peptization, Langmuir 5(2), 534-538. 

The first term in the right-hand side of the Equation 5.203 corresponds to an ideal solution, whereas the second term takes into account the effect of electrostatic interactions between the ions (the same effect is accounted for thermodynamically by the activity coefficient see Equation 5.31). 

One might expect that magnetic interactions arise from dipole-dipole interactions between the magnetic moments, but the fact is that magnetic interactions are largely effects of electrostatic interactions. To see this, we can consider a Hydrogen molecule with the Hamiltonian ... 

Liu H, Skibinska L, Gapinski J, Patkowski A, Fischer EW, Pecora R. Effect of electrostatic interactions on the structure and dynamics of a model polyelectrolyte. I. Diffusion. J Chem Phys 1998 109 7556—7566. 

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