Correlation of core electron binding energies with the average potential at a nucleus: Carbon 1s and extended Huckel theory valence molecular orbital potentials

Binding energy shifts spanning a range of 9 eV for carbon 1s electrons in twenty different environments have been correlated with the properly calculated average potential at the carbon nucleus due to the other nuclei (with nuclear charges appropriately reduced by their core electrons) and the valence electrons in molecular orbitals from extended Huckel theory. The linear least squares correlation thus obtained gives a good fit to the shifts, as contrasted to a more scattered fit obtained with calculated carbon atomic charges. A brief discussion is given of the results and of implications for this approach of using valence molecular orbital potentials for core electron binding energy shifts in other cases.