Electrostatic potential, molecular interactive behavior

In the next chapters, one or several of those formalisms are used to describe some aspects of molecular behavior toward other molecules in terms of properties such as electrostatic potential, nonbonded interactions, behavior in solvents, reactivity and behavior during interaction with other molecules, and finally similarity on the basis of nonquantum and quantum properties. 

The use of the electrostatic potential in analyzing and predicting molecular interactive behavior and properties has increased remarkably over the past 25 years. In 1980, it was still reasonable to hope to at least mention, in one lengthy review chapter (Politzer and Daiker 1981), all of the papers that had been published in this area. In 1996, such an objective would be ridiculous. This popularity can be attributed to (a) the insight that V(r) can provide, especially into noncovalent interactions, and (b) the widespread availability of computational software packages of which it has become a standard feature. 

The Electrostatic Potential as a Guide to Molecular Interactive Behavior... 

Our focus in this chapter has been upon the relationship of the electrostatic potential to molecular interactive behavior. However the significance of V(r) goes far beyond, as we shall briefly point out. A more detailed overview, with relevant references, has been given by Politzer and Murray [47]. 

Rolitzer, R Murray, J. S. 2009. The electrostatic potential as a guide to molecular interactive behavior. In Chemical Reactivity Theory A Density Functional View, edited by R. K. Chattaraj, 243-254. Boca Raton, FL CRC Riess. 

The electrostatic potential V r) that is created in the space around a molecule by its nuclei and electrons is a well-established guide to chemical reactivity and molecular interactive behavior. " Unlike many of the other quantities used now and earlier as indices of reactivity, e.g., atomic charges, the electrostatic potential is a real physical property, one that can be determined experimentally by diffraction methods as well as computationally. However, V r) is most commonly obtained computationally. With the recent advances in computer technology, it is currently being applied to a variety of significant chemical systems. 

The macroscopic property of interest, e.g., heat of vaporization, is represented in terms of some subset of the computed quantities on the right side of Eq. (3.7). The latter are measures of various aspects of a molecule s interactive behavior, with all but surface area being defined in terms of the electrostatic potential computed on the molecular surface. Vs max and Fs min, the most positive and most negative values of V(r) on the surface, are site-specific they indicate the tendencies and most favorable locations for nucleophilic and electrophilic interactions. In contrast, II, a ot and v are statistically-based global quantities, which are defined in terms of the entire molecular surface. II is a measure of local polarity, °fot indicates the degree of variability of the potential on the surface, and v is a measure of the electrostatic balance between the positive and negative regions of V(r) (Murray et al. 1994 Murray and Politzer 1994). 

The macroscopic property of interest, e.g., heat of vaporization or sublimation, is represented by some subset (in most cases two suffice) of the computed properties on the right side of equation (8). All of the latter are defined in terms of the surface electrostatic potential except for surface area (which is calculated directly from the number of points on the molecular surface), and are measures of various aspects of a molecule s interactive behavior. 

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