CORRELATION-EFFECTS IN-CORE AND VALENCE PHOTOELECTRON-SPECTRA OF ALKENE MOLECULES

The core, the inner and outer valence ionization spectra of propene, 1-butene, 1-pentene, cis-butene, trans-butene and iso-butene have been calculated at the ab initio configuration interaction (CI) level, in order to analyze the influence of different substitutions on the double bond on the appearance of the spectra. The CI schemes adopted, i.e. 3h-2v(pi) + 2h - 1p CI for the core part, 2h-1v CI for the valence part and 2h-1p CI for core and valence, have proven to be adequate for the description of correlation effects which cause the appearance of complex structures in the spectra. Satisfactory reproduction of the experimental features has been achieved and for their simplicity the CI schemes adopted can be put forward for the calculation of the spectra of larger molecules of the same type which allows a clearer insight of the evolution of correlation effects with the increasing complexity of the systems.