Prediction of electrostatic

The electronic structure of a molecule holds a vast amount of information. Harnessing this information in a usable form is of immense value for predictive toxicology. It is of particular use for the prediction of electrostatic and covalent interactions such as those resulting in mutagenicity... 

Sternberg, M., F. Hayes, A. Russell, P. Thomas and A. Fersht. (1987). Prediction of electrostatic effects of engineering of protein charges. Nature. 330 86. 

An unanswered question does remain regarding the extension of our findings to predict the adsorption characteristics of human hepatitis type A. This virus is the etiologic agent of infectious hepatitis, which is considered to be the most serious problem in the transmission of waterborne virus disease (i). It is similar to other enteroviruses in terms of size (27 nm in diameter), density in CsCl gradients (1.34 g cm ), stability in the presence of chemical and physical agents, and probable nucleic acid type (69). However, electrokinetic properties of this virus have yet to be characterized. This information is required before accurate predictions of electrostatic components of adsorption can be made for this virus. 

Buckingham A D, Fowler P W and Stone A J 1986 Electrostatic predictions of shapes and properties of van der Waals molecules Int. Rev. Phys. Chem. 5 107... 

The results of electrostatic potential calculations can be used to predict initial attack positions of protons (or other ions) during a reaction. You can use the Contour Plot dialog box to request a plot of the contour map of the electrostatic potential of a molecular system after you done a semi-empirical or ab initio calculation. By definition, the electrostatic potential is calculated using the following expression ... 

Honk et al. concluded that this FMO model imply increased asynchronicity in the bond-making processes, and if first-order effects (electrostatic interactions) were also considered, a two-step mechanisms, with cationic intermediates become possible in some cases. It was stated that the model proposed here shows that the phenomena generally observed on catalysis can be explained by the concerted mechanism, and allows predictions of the effect of Lewis acid on the rates, regioselectivity, and stereoselectivity of all concerted cycloadditions, including those of ketenes, 1,3-dipoles, and Diels-Alder reactions with inverse electron-demand [2],... 

As the corrosion rate, inclusive of local-cell corrosion, of a metal is related to electrode potential, usually by means of the Tafel equation and, of course, Faraday s second law of electrolysis, a necessary precursor to corrosion rate calculation is the assessment of electrode potential distribution on each metal in a system. In the absence of significant concentration variations in the electrolyte, a condition certainly satisfied in most practical sea-water systems, the exact prediction of electrode potential distribution at a given time involves the solution of the Laplace equation for the electrostatic potential (P) in the electrolyte at the position given by the three spatial coordinates (x, y, z). 

Similarly, examples of barriers arising largely from simple steric hindrance can be found, as for instance in the hindered diphenyls.35 On the other hand there are many arguments suggesting that this is not the important force in ethane and similar molecules. It would be difficult to understand the relatively slow fall in barrier from ethane to methyl silane to methyl germane on a van der Waals repulsion basis. Furthermore, the small effect of substituting F, Cl, or Br on one end would also seem mysterious. The equilibrium orientation in propylene is opposite to the predictions of one of the quantitative van der Waals theories. Finally, the apparently small effect of bending back the C—H bonds is not in accord with either the electrostatic or van der Waals pictures. 

The electrostatic and spin-orbit parameters for Pu + which we have deduced are similar to those proposed by Conway some years ago (32). However, inclusion of the crystal-field interaction in the computation of the energy level structure, which was not done earlier, significantly modifies previous predictions. As an approximation, we have chosen to use the crystal-field parameters derived for CS2UCI6 (33), Table VII, which together with the free-ion parameters lead to the prediction of a distinct group of levels near 1100 cm-. Of course a weaker field would lead to crystal-field levels intermediate between 0 and 1000 cm-1. Similar model calculations have been indicated in Fig. 8 for Nplt+, Pu1 "1 and Amlt+ compared to the solution spectra of the ions. For Am t+ the reference is Am4" in 15 M NHhF solution (34). 

Ion Radius ratio Predicted coordination number Observed coordination number Strength of electrostatic bonds... 

Haeberlein, M., Brinck, T. Prediction of water-octanol partition coefficients using theoretical descriptors derived from the molecular surface area and the electrostatic potential. J. Chem. Soc. 

Helgeson, H.C. and Kirkham, D.H. (1974) Theoretical prediction of the thermodynamic behavior of aqueous electrolytes at high pressures and temperatures I Summary of the thermodynamical electrostatic properties of the solvent. Am. J. Scl, 274, 1089-1198. 

The individual terms in (5.2) and (5.3) represent the nuclear-nuclear repulsion, the electronic kinetic energy, the electron-nuclear attraction, and the electron-electron repulsion, respectively. Thus, the BO Hamiltonian is of treacherous simplicity it merely contains the pairwise electrostatic interactions between the charged particles together with the kinetic energy of the electrons. Yet, the BO Hamiltonian provides a highly accurate description of molecules. Unless very heavy elements are involved, the exact solutions of the BO Hamiltonian allows for the prediction of molecular phenomena with spectroscopic accuracy that is... 

The elasticity can be related to very different contributions to the energy of the interface. It includes classical and nonclassical (exchange, correlation) electrostatic interactions in ion-electron systems, entropic effects, Lennard-Jones and van der Waals-type interactions between solvent molecules and electrode, etc. Therefore, use of the macroscopic term should not hide its relation to microscopic reality. On the other hand, microscopic behavior could be much richer than the predictions of such simplified electroelastic models. Some of these differences will be discussed below. 

The adsorption of HPAM on sand (Figure 4) is not detected below a threshold value of Ca2+ due to strong electrostatic repulsion between the polyelectrolyte and the highly charged negative surface. This threshold value, which was also observed in the case of monovalent ions (9), represents the point where the critical adsorption energy is overcome, and once this value is surpassed, adsorption increases sharply. This form of adsorption behavior is in line with predictions of theories on polyelectrolyte adsorption (20). 

Our discussion in this chapter will focus on the use of the electrostatic potential as a means to understanding and predicting chemical interactions. First, we will examine some of its properties and important features. Next, we will discuss methodology. Finally we will review some recent applications of the electrostatic potential in areas such as hydrogen bonding, molecular recognition, and understanding and prediction of a variety of physio-chemical properties related to molecular interactions. Our intent has not been to provide a complete survey of the ways in which the potential has been used, many of which are described elsewhere (Politzer and Daiker 1981 Politzer, Laurence, and Jayasuriya 1985 Politzer and Murray 1990 Politzer and Murray 1991 Politzer and Truhlar 1981 Scrocco and Tomasi 1973), but rather to focus on some diverse examples. 

Weinstein, H., R. Osman, J. P. Green, and S. Topiol. 1981a. Electrostatic Potentials as Descriptors of Molecular Reactivity The Basis for Some Successful Predictions of Biological Activity. In Chemical Applications of Atomic and Molecular Electrostatic Potentials. P. Politzer and D. G. Truhlar, Eds. Plenum Press, New York. 

Sugawara, M., Takekuma, Y., Yamada, H., Kobayashi, M., Iseki, K., Miyazaki, K., A general approach for the prediction of the intestinal absorption of drugs regression analysis using the physicochemical properties and drug-membrane electrostatic interaction, J. Pharm. Sci. 1998, 87, 960-966. 

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