Quantum chemical calculations charge distribution

Effects of nitrogen substitution can be predicted by quantum chemical calculations (42,43), or more qualitatively by examining the charge distribution in the relevant carbocations. When a carbocation is generated at C-l, the positive charge can be delocalized as shown below. 

This reaction, inaptly named condensation reaction43, proceeds either by a nucleophilic substitution mechanism or by insertion of dichlorogermylene into the C—Cl bond. The nucleophilic substitution mechanism is doubtful. In accordance with quantum-chemical calculations, the negative charge in the anion GeCh- is distributed on chlorine atoms and a movement of anion to the cation from the rear results in Cl- loss and GeCl2 formation39. 

Mikheikin et al. (11) have formulated an alternative approach where terminal valencies are saturated by monovalent atoms whose quantum-chemical parameters (the shape of AO, electronegativity, etc.) are specially adjusted for the better reproduction of given characteristics of the electron structure of the solid (the stoichiometry of the charge distribution, the band gap, the valence band structure, some experimental properties of the surface groups, etc.). Such atoms were termed pseudo-atoms and the procedure itself was called the method of a cluster with terminal pseudo-atoms (CTP). The corresponding scheme of quantum-chemical calculations was realized within the frames of CNDO/BW (77), MINDO/3 (13), and CNDO/2 (30) as well as within the scope of the nonempirical approach (16). 

Because of the low excess energy, a multi-collision interaction leads to an encounter situation combined with structural optimization to something like an asymmetric charge transfer complex which here is identical with an encounter complex. Then the delayed electron transfer takes place, as mentioned above. This can be well illustrated in terms of the quantum-chemically calculated electron and charge distributions of the involved orbitals as shown in Fig. 8. 

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