Giant correlation effects in the photoelectron spectrum of Ni(C3H5)(2): clues from accurate calculation of ionization cross-sections

Several general issues relating to the strong correlation effects present in the ionic states and the interpretation of molecular photoelectron spectra are discussed in the context of the Ni(C3H5)(2) molecule, and the problematic assignment of its spectrum is considered. Accurate calculations of photoionization cross-sections relative to all the valence ionizations are computed and compared with the available experimental evidence. It is shown that most ambiguities are resolved by a careful analysis of cross-section profiles and branching ratios, which reveal a wealth of details on the complex electronic structure of this molecule.