An Electrostatic Model

As a result of the strong electrostatic interaction in the inner rear region the /-value [cf. Eq. (14)] increases towards 1, because 2 4. This higher screening inside, in comparison to the outside value / = 0.76, causes a bending of DNA around the histone core. This model explains the influence of ionic strength  

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The von Smoluchowski equation must be corrected when the partners are ions to account for attractive or repulsive forces. They can be approximated by an electrostatic model. The quantity by which Eq. (9-10) or (9-13) is to be multiplied is... 

The effective pressure produced by the electrodes on the elastomeric film is a function of applied voltage and can be derived by using an electrostatic model proposed by Pelrine et al. This pressure P is given by... 

Wood and Blundy (2001) developed an electrostatic model to describe this process. In essence this is a continuum approach, analogous to the lattice strain model, wherein the crystal lattice is viewed as an isotropic dielectric medium. For a series of ions with the optimum ionic radius at site M, (A(m))> partitioning is then controlled by the charge on the substituent (Z ) relative to the optimum charge at the site of interest, (Fig. 10) ... 

Tremaine, P.R. and Goldman, S., "Calculations of Gibbs Free Energies of Aqueous Electrolytes to 350°C from an Electrostatic Model for Ion Hydration", Jr. Phys. Chem., in press. Helgeson, H.C., "Evaluation of Irreversible Reactions in Geochemical Processes Involving Minerals and Aqueous Solutions - I Thermodynamic Relations", Geochimica et Cosmochimica Acta, (1968), 3, 853. 

Electrostatic Models. For polar reactions it is possible to develop an electrostatic model. This is necessarily an oversimplification, though it does allow the gross features of such systems to be delineated. Thus, when a complex and the free ligand both react with the same gross mechanism, it is possible to estimate the electrostatic contribution to the change in entropy of activation when the reaction is polar or ionic. Following Laidler (21) we can estimate the electrostatic contribution to the entropy of activation as ... 

Obtained through with i ip being estimated according to an electrostatic model. 

The simplest rationalization of the effect in Fig. 6 invokes an electrostatic model. The isoelectric point of GO from A. niger equals 4 (17) and its total charge is -60 at pH 7 (93). It could be hypothesized that the... 

A very good picture of some of the properties of hydrogen compounds can be obtained with the aid of an electrostatic model, but we must be careful not to conclude that all the hydrogen compounds are therefore ionic in character. In addition to NHS, there are two other nitrogen compounds, hydrazine H2NNH2 and hydroxylamine NH2OH, which have properties not fundamentally dissimilar to those of ammonia. It is not possible to devise a plausible electrostatic model for these compounds because of the bond between like atoms. In addition to water there is also the compound hydrogen... 

Conclusion Ionic crystals may be viewed quite simply in terms of an electrostatic model of lattices... 

A comparative study of gas-phase and liquid-phase CH acidity of a-substituted cyclopropanes has verified the correctness of an electrostatic model for the effect of solvation on equilibrium acidity 127 among variants of the LCAO MO method, only the semiempirical AMI method accurately predicted the proton affinity of the conjugate carbanions effects of solvation on protonation rates have been desegregated. 

Another version of an electrostatic model is that of De Wit et al. (1990, 1991, 1993a, b). In this model a continuous distribution concept and electrostatic model are combined. 

A localized molecular orbital representation is the closest approach that can be achieved, for a given determinantal wavefunction, to an electrostatic model of a molecule 44>. With truly exclusive orbitals, electron domains interact with each other through purely classical Coulombic forces and the wavefunction reduces, for all values of the electronic coordinates, to a single term, a simple Hartree product. 

The phenomenon of the nephelauxetic effect cannot be interpreted in the framework of an electrostatic model which considers exclusively first-order crystal field effects. The observed band shifts could be due to second-order crystal field effects. However, the theoretical values of the second-order crystal field effects are of the order of 10 cm-1 or so [40,41] and cannot account for the experimentally observed band shifts, which in some cases are as high as 100 to 1000 cm 1. 

The calculation of the dipole moment of the activated complex was based on an electrostatic model of Kirkwood, Laidler and Eyring [cf. Section 5.4.3) [2, 11]. The value for the dipole moment of the zwitterion was estimated as the vector sum of the partial moments [94]. 

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