Natural charging

The electrostatic force is directly proportional to the net charge of an aerosol particle. Therefore, effective charging of the particles is of great importance. Airborne particles are normally charged either due to their birth processes or due to charge transfer from gas ions to particles. The natural charging of particles is normally so weak that it has no practical importance for electrostatic air cleaning. 

Fujino, M., Ogata, S., and Shinohara, H., The electric potential distribution profile in a naturally charged fluidized bed, Funt. Kog. Kaishi, 20 280-289 (1983) English translation inInt. Chem. Engrg., 25 149-159 (1985)... 

Although orbital hybridizations and molecular shapes for hypovalent metal hydrides of the early transition metals and the normal-valent later transition metals are similar, the M—H bonds of the early metals are distinctly more polar. For example, metal-atom natural charges for YH3 (+1.70), HfH4 (+1.75), and TaHs (+1.23) are all significantly more positive than those (ranging from +0.352 to —0.178) for the homoleptic hydrides from groups 6-10. Indeed, the empirical chemistry of early transition-metal hydrides commonly reveals greater hydricity than does that of the later transition-metal hydrides. 

Problem Given the monomer natural charges (Qt) and the equilibrium Cartesian coordinates (xi, yt, z,) of the water dimer, H20- H20... 

The actual natural charge in the cyclic pentamer is qnat = 0.570, which makes the Coulombic point-charge estimate entirely unrealistic.) Thus, no matter how q is chosen, a simple Coulombic point-charge model will give >10% errors for one or the other of these clusters. 

Fig. 12 Correlation between the calculated activation energy of the Bergman cyclization and the product of natural charges at the terminal acetylenic atoms of benzannelated enediynes. Only para substituents obey the correlation. Adapted from reference49.

In studies on solvent effects involving variation in the composition of two component mixtures, similar types of outer-sphere interactions yield preferential solvation wherein the solvent composition of the outer-sphere may differ markedly from the bulk solvent composition. Supporting electrolyte species and buffer components may also participate in outer-sphere interactions thereby changing the apparent nature (charge, bulk, lability) of the reacting solvated metal ion or metal complex as perceived by a reacting ligand in the bulk solvent. 

Table 1 NBO charges of the stationary points (black natural charge, red change to the previous stationary point B3LYP/6-31++G(d,p)...

Fig. 12 LUMO energy (o qh) (a) and natural charge of the hydroxyl proton (b) vs aggregation state of HFIP...

TABLE 3. The natural charge population in monomeric and aggregated structures of CH2=CHOLi and corresponding solvated forms using method A (B3LYP/6-31+G //6-31+G ) and method B (B3LYP/6-311+G //6-31+G ) calculations... 

TABLE 4. Coordination energies and natural charges of protonated hthium-complexed hydrocarbons" illustrated in Figure 15. Reproduced with permission from Reference 18. Copyright 1996 American Chemical Society... 

Subsequently, DFT methods (B3LYP functional ) were employed to compute (1) natural charges from which changes in charges are mapped out for comparison with the NMR-based conclusions, (2) GIAO-NMR to predict the chemical shifts for comparison with the experimental results, and (3) nuclear-independent chemical shift (NICS) in order to evaluate relative aromaticity in different rings. Finally, solvent effects were estimated by the polarized continuum model (PCM). In selected cases, parallel DNA-binding studies (with MCF-7 human mammary... 

Radiation quality is defined by the nature, charge, and energy spectrum of the particles and can be characterized by the linear energy transfer (LET) or, alternatively, by the micro-dosimetric spectra at the point of interest under the actual irradiation conditions. 

The relative Michael-acceptor abilities of a variety of substituted aromatic and aliphatic nitroalkenes have been elucidated by computational methods. Several global and local reactivity indices were evaluated with the incorporation of the natural charge obtained from natural bond orbital (NBO) analysis. Natural charges at the carbon atom to the NO2 group and the condensed Fukui functions derived by this method were found to be consistent with the reactivity.187... 

The mention of radical ions three paragraphs ago is part of a general truth PET is naturally charge separating within electroneutral systems. So PET... 

Table 5.15 Comparing Mulliken, electrostatic potential and natural charges, and Mulliken and Lowdin bond orders, at various levels, for hydrogen fluoride. The geometry used in each case corresponds to the method/basis set for that charge or bond order, but any reasonable geometry should give essentially the same results. There are no experimental data...

Outside the QTAIM realm, the main definitions of atomic charges are Mulliken charge, electrostatic charge, and natural charge [3]. Values can differ considerably from one method to another, but the trend with a particular method can provide useful information. None of these three methods of assigning charge claims to be unique. 

Atom no. Nature Connections Bond nature Charge... 

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