Ionic fragmentation of carbon 1s excited metallocenes

Ionic fragmentation following the decay of carbon 1s excited and ionized states of ferrocene and nickelocene has been studied through measurements of the total cation yield spectra, photoion yield curves of mass selected fragments and photoion-photoion coincidence (PIPICO) spectra. Ionization yield spectra (ions per absorbed photon) and PIPICO yield spectra (ion pairs per absorbed photon) are derived by comparison of the results to the true absorption spectra, derived from inner shell electron energy loss measurements. These results are discussed in relation to cation fragmentation of valence shell excited metallocenes, and dissociative double ionization processes occurring in other organometallic complexes. Charge separation mechanisms of doubly charged metallocenes are proposed. The Fe 2p and Ni 2p spectra of these species are also reported.