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|Type:||Artigo de periódico|
|Title:||Characteristic substituent-shift models for carbon 1s ionization energies and mean dipole-moment derivatives|
de Oliveira, AE
|Abstract:||Characteristic substituent-shift models for carbon mean dipole-moment derivatives are determined for the halomethanes, fluorochloroethanes, and some other small molecules. These models are analogous to those reported earlier for core ionization energies measured by X-ray photoelectron spectroscopy and are to be expected since Siegbahn's simple potential model relates these to mean dipole-moment derivatives obtained from infrared spectral data. Linear models relating carbon 1s ionization energies and mean dipole-moment derivatives to the number of fluorine, chlorine, bromine, and iodine atoms substituting hydrogen atoms in the halomethanes are reported. The regression coefficients in these models are similar to the coefficients for the fluorine and chlorine atoms found in linear models derived for the mean dipole-moment derivatives and carbon 1s ionization energies of the fluorochloroethanes. The signs of the coefficients in the fluorochloroethane model indicate that the alpha carbon becames more positive and the beta carbon more negative upon fluorine substitution for hydrogen. Standard derivative values of -0.52+/-0.05, -0.25+/-0.05, -0.18+/-0.03, -0.17+/-0.03, and -0.01+/-0.01 e are proposed for the fluorine, chlorine, bromine, iodine, and hydrogen atoms of saturated fluorochlorohydrocarbons. Characteristic substituent shifts for Mulliken, CHELPG, and Bader charges of the carbon atoms in these molecules are also investigated.|
|Editor:||Amer Chemical Soc|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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