The Core and Valence Hole Spectra of Ethylene

It is very interesting to compare this with the Is core level spectrum of 02m), which can be regarded as the equivalent (united) diatomic molecule of C2H4. Much in the same 

The 1 Jb3U (Jr,) is the only valence hole that cannot fluctuate, there being no occupied ji levels for the hole to fluctuate to. It therefore remains delocalized, and since the monopole relaxation shift is very small, the level shift is dominated by Fermi sea correlations. All the other valence orbitals can fluctuate and have substantial relaxation shifts due to 

Quasi-Particle Properties of Hole Levels in Molecules 

Compared with experiment7 (Fig. 55) it seems that the 1 j g, 3ag and 1 b outer valence holes become shifted by 1-1.5 eV and the 2blu (2 a ) inner valence hole by more than 2 eV due to fluctuation/localization, precisely along the lines previously discussed for N2 and QH2. Concerning the 2ag inner valence region, it looks very similar to the 2ae 

7 Validity of the Molecular Orbital and Quasi-Particle Concepts 

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