Electron population analysis

Electronic Population Analysis on LCAO-MO Molecular Wave Functions I... 

Stewart, R.F. (1976) Electron population analysis with rigid pseudoatoms, Acta Crystallogr., A, 32, 565-574. 

Mulliken, R. S. (1955) Electronic population analysis on LCAO-MO molecular wave functions. I. J. Chem. Phys. 23, 1833-1840. 

Most of the reactivity problems described in Sect. VI C have been treated recently by methods based on the electronic Overlap Population concept as introduced in the Electronic Population analysis of R. S. MuUiken. In fact the studies of the problems of Sect. VI C have established the general usefulness and apphcability of electronic overlap populations as reactivity measures for other excited- and ground-state reactions. The most important advantage of the electronic overlap population method of reactivity analysis is the possibihty provided for relating bond forming reactivity of two initially nonbonded atoms to the strength of their electronic interaction. 

A common structural motif in peroxides of the type R3C—O —0°—Y (R = alkyl, aryl, fluorine, Y = R3C or H) is a marked distortion of the R3C fragment from tetrahedral geometry. The R—C bond, which is located in the C—O —plane, exhibits the smallest of the three R—C—O angles (Table 4) °. This tetrahedral distortion has been interpreted, on the basis of an electron population analysis, with a ctr c [Pg.103]

Hansen NK, Coppens P (1978) Electron population analysis of accurate diffraction data. 6. Testing aspherical atom refinements on small-molecule data sets. Acta Crystallogr A 34 909-921... 

R. S. Mulliken,/. Chem. Phys., 23, 1833, 1841 (1955). Electronic Population Analysis on LCAO-MO Molecular Wavefunctions. I. (no subtitle). II. Overlap Populations, Bond Orders, and Covalent Bond Energies. 

Core and valence electrons can be divided based on a criterion of whether their distributions and populations are changed or not owing to bond formation. The electron population analysis conventionally uses spherical form factors, f, which are given by the spherically averaged Fourier transform of electron-density distributions. 

In metal oxides and silicates, the net charges of transition metal atoms are quite different. Table III shows the net charges of metal atoms in these crystals, which are slightly neutralized but almost equal to their oxidation numbers. The ionic characters of these crystals may be demonstrated by the electron population analysis of the CoA1204 crystal. The net charges of Co(II), Al(III), and O(II) atoms were estimated by the ELS method to be +1.5(1), +2.8(1), and -1.8 e, respectively (84). 

Mulliken, R.S., Electronic population analysis on ICAO—MO molecular wave functions II. Overlap populations, bond orders, and covalent bond energies. J.Chem.Phys. (1955) 23 1841-1846. 

Table 1 Summary of Gas Phase Electron Population Analysis for Re and Cl Centers Involved in Reaction of Cl Atom Abstraction by Re(CO)5 Radical... 

Stewart RF (1973) Electron population analysis with generalized X-ray scattering factors higher multipoles. J Chem Phys 58 1668-1676... 

P. Coppens, R. Boehme, P. F. Price and E. D. Stevens, Electron population analysis of accurate diffraction data. 10. Joint X-ray and neutron data refinement of structural and charge density parameters, Acta Cryst. A37, 857-863 (1981). 

It has been proposed that generalized x-ray-scattering factors be used as a basis for electron population analysis.19 In this model the core... 

Frequently the work involved conjugated molecules to which energy calculations and a theoretical dipole moment was obtained that could be compared with the experimental data. With the advent of NMR. and ESR. spectroscopy other observables became available, and theory was successfully applied to the interpretation of these spectra. However, very little was done in the field of real chemistry, that is, in the study of reaction mechanisms and reaction rates. Over the last decade the availability of large electronic computers, the introduction of approximate but reliable quantum mechanical methods which include all the electrons, or at least all valence electrons in a molecular system and the discovery of the rules of orbital symmetry have led to a significant change of the situation. 

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