Electrostatic potential, molecular interactive electronic density function

Such an expression has previously been used for comparative purposes, for the study of interaction between two molecular species, by computing the electrostatic potential of the first partner and by assuming some point charge model as representative of the charge distribution of the second partner. We also plan to extend this concept in a more subtle way by using an electron density contour map to describe the charge distribution of the second partner as a function of the space surrounding this second partner. 

Volkov, A., Koritsanszky, T, and Coppens, P. [2004]. Combination of the exact potential and multipole methods [EP/MM] for evaluation of intermolecular electrostatic interaction enei ies with pseudoatom representation of molecular electron densities, Chem. Phys. Lett 391, pp. 170-175, dol 10.1016/j.cplett.2004.04.097. von Lilienfeld, 0. A., Tavernelli, 1., Rothlisberger, U., and Sebastian , D. [2004]. Optimization of effective atom centered potentials for London dispersion forces in density functional theory, Phys. Rev. Lett 93,15, p. 153004. 

The orientational structure of water near a metal surface has obvious consequences for the electrostatic potential across an interface, since any orientational anisotropy creates an electric field that interacts with the metal electrons. Hydrogen bonds are formed mainly within the adsorbate layer but also between the adsorbate and the second layer. The left side of Fig. 20 shows the orientational distribution of the molecular dipole moment, relative to the surface, normal in various distance ranges from the Hg(lll) surface. Additionally, the oxygen density profile is plotted. The baselines between distribution functions cut through the density profile. The distribution function in each panel on the left side is for the subset of molecules that are located in the distance range between these lines on the right side. Over the first peak in the density profiles (panels a tod), there are almost no molecules whose dipole moment is perpendicular to the surface, as would be expected for an isolated molecule on... 

In recent years, the topological analysis of the three-dimensional scalar fields [87-95], such as electron density [55, 67, 92, 95-97], the Laplacian of the electron density [68, 92], the electron localization function (ELF) [94, 98], and molecular electrostatic potential, have been widely used to discern chemical structure and reactivity. This procedure, named quanmm chemical topology (QCT) [99] has been utilized for the study of chemical stmcture and reactivity [100-106]. Since its origins, the well-known approach of the atoms in molecules quantum theory (QTAIM), has evolved to be an invaluable tool for the chemical interpretation of quantum mechanical data, which relies on the properties of the electron density p(r) when atoms interact. Excellent reviews on QTAIM methods have been published elsewhere [69, 96, 107-109]. 

At such distances, the use, as an interpretative tool, of the molecular electrostatic potential (which is simply the Gateaux derivative of the molecular classical electrostatic energy functional with respect to the electron density) becomes arguable since classical electrostatics does not exclusively drive the studied interactions. This... 

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