Artificial charge distribution

In exposures of humans to artificially generated aerosols, where the information is to be relevant to ambient aerosols, several factors are important the particle diameter distribution must be fairly constant and fall within size ranges typical for the given compound in the ambient air, the chemical composition of the aerosol must be stable and predictable, and the electric charge distribution of the aerosol must simulate that of normal atmospheric aerosols. 

Most commonly used is certainly the molecular electrostatic potential. It can be derived from any kind of charge distribution. Usually, the MEP is first calculated on a grid and subsequently transformed to the sphere or Gaussian representation. Quite important is the electron density distribution, which closely models the steric occupancy by a molecule. Other approaches utilize artificial fields for physicochemical properties commonly associated with binding, like a field for the hydrophobicity [193] or H-bonding potential [133,194]. 

Not only is hybridization an artificial simulation without scientific foundation, but even the assumed "orbital shapes" that it relies upon, are gross distortions of actual electron density distributions. The density plot shown above, like all textbook caricatures of atomic orbitals, is a misrepresentation of the spherical surface harmonics that describe normal excitation modes of atomic charge distributions. These functions are defined in the surface of the charge-density function, as in Fig. 2.13, and not at r = 0, as shown in Figure 2.16. 

The Coulomb force is mediated by (virtual) photons. Following Faraday, we introduce the artificial concept of the electric field E due to an electric charge distribution p(r) ... 

The main shortcoming of the cluster approach consists of the scission of the chemical bonds between terminal atoms of a cluster and the rest of a lattice. As a result, so-called dangling bonds occur at the terminal atoms of a cluster, artificial electron surface states appear in the partially occupied band, and the charge distribution is disturbed. A cluster in this case possesses too many surface atoms. Unfortunately, to obtain a better surface/bulk ratio, one should consider such large clusters that the approach becomes useless. 

In these non-alternating compounds the M.O. representation, which foregoes the setting up of special chemical formulae and gives only bond orders and charge distribution for the various bonds, is greatly preferable to the very artificial V.B. interpretation in this case. 

Neodymium in natural and artificial apatite is characterized by anomalous distribution of luminescence intensity in the groups at 1.06 and 1.3 pm. In each of these spectral groups there is one fine whose intensity exceeds many times the intensity of the remaining fines of said group (Morozov et al. 1970). In laser-induced luminescence of natural apatites we also found somewhat different luminescence spectra (Eig. 4.3). Decay times of these fines are rather close and it is possible to suppose that all Nd occupy the Ca(I) sites with different charge compensations. 

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