Theory electrostatic model

P. Maladidre. Compt. rend. 226, 1600-1 (1948). Theory electrostatic model energy, vibrational frequencies, v, . 

Otdel. Kkim. Nauk 1950, 162-8 (1950). Theory electrostatic models of HF dimers, hexamers, energy. 

Harder E, Anisimov VM, Vorobyov IV, Lopes PEM, Noskov SY, MacKerell AD, Roux B (2006) Atomic level anisotropy in the electrostatic modeling of lone pairs for a polarizable force field based on the classical Drude oscillator. J Chem Theory Comput 2(6) 1587-1597... 

The role of surface viscosity is demonstrated in Figure 8 with the constant-potential and weak overlap electrostatic model. We note that the underlying theory is restricted to large values... 

Figure 10. Comparison of the critical-capillary-pressure data of Khatib, Hirasaki and Falls (5) (darkened circles) to the proposed dynamic foam stability theory (solid line). Best fitting parameters for the constant-charge electrostatic model are listed.

In the o.s. reaction, the ion pair A+ - B is formed in a first step. The corresponding equilibrium constant can usually be obtained from simple electrostatic models. In this "ideal" case specific chemical interactions can be neglected and the rate constant of the E.T. step follows the theory of R.A. Marcus (see for example Marcus, 1975, or Cannon, 1980). In the i.s. reaction each of the three steps in reaction (9.2) may determine the reaction rates. The lability of the coordinated ligands at the... 

In general, electrostatic theory is not able to reproduce correct energy surfaces as a whole since the compensation of errors mentioned above holds only around the energy minima (see p. 25). Furthermore, the various spectral data, especially IR, RAMAN and NMR results, which became accessible during the last ten years cannot be interpreted at all by electrostatic models. Many theoreticians feel, therefore, that there is a need for more accurate calculations on ion-molecule complexes based upon quantum mechanics. 

The ionic model divides the forces acting on atoms into an electrostatic component that can be calculated using classical electrostatic theory and a short-range component that is determined empirically. The previous chapter explored the properties of the classical electrostatic field. This chapter explores the properties of the empirically determined short-range force which is represented in the electrostatic model by the bond capacitance, C,y, defined in eqn (2.8). Rather than try to determine the values of Cy directly, it is better to step back and look at the way in which the bond valence model developed historically. Its connection with the electrostatic model of Chapter 2 will then become apparent. 

The theory needed to explain why normally diamagnetic compounds should develop singlet and triplet states of very nearly equal energy has been developed by Maki (139-161) Ballhausen and Liehr have come to similar conclusions on much simpler grounds (11). Maki (159) has used purely electrostatic models to determine the splittings of the states of a nickel(II) ion in different symmetries. The results obtained have been tested by attempting to assign the near infrared and visible spectra of suitable complexes with them (160, 161). 

J. O M. Bockris, D. B. Matthews, and S. U. M. Khan, J. Res. Inst. Catal. 22 1 (1974). The AG°X calculated from the electrostatic model of Weiss-Marcus is discrepant with experimental trends, but a vibrational energy based theory fits well. 

Over the years, various other theories and models have been proposed for predicting salt effect in vapor-liquid equilibrium, including ones based on hydration, internal pressure, electrostatic interaction, and van der Waals forces. These have been reviewed in detail by Long and McDevit (25), Prausnitz and Targovnik (31), Furter (7), Johnson and Furter (8), and Furter and Cook (I). Although the electrostatic theory as modified for mixed solvents has had limited success, no single theory has yet been able to account for or to predict salt effect on equilibrium vapor composition from pure-component properties alone. 

Thus the contribution of the structured ionic cloud to the total potential at the surface of the central ion will not be as it is in the DH theory, and because the electrostatic model requires an equipotential surface to be maintained there, a new model is needed. We therefore approximate an ion to a dielectric sphere of radius a, characterized by the dielectric constant of the solvent D, and having a charge Q, residing on an infinitesimally thin conducting surface. This type of model has been exploited by previous workers (17,18) and may be reconciled with a quantum-mechanical description (18). 

Valence-shell electron pair repulsion (VSEPR) theory gives reasonably accurate predictions of bond angles in a molecule. VSEPR theory uses a simple electrostatic model in which groups of electrons around a central atom repel one another and occupy positions as far apart as possible. The number of electron groups, called the steric... 

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