In order to investigate outer valence ionic states of open-shell metallocenes, we have applied two-dimensional collision-energy/electron-energy- resolved Penning ionization electron spectroscopy (2D-PIES) upon collision with metastable He*(23S) excited atoms as well as a high level ab initio molecular orbital calculation (the partial third-order quasiparticle theory of the electron propagator (P3)) to ionization from neutral ground states of vanadocene (4A2g) and nickelocene (3A 2g). Assignments of observed Penning ionization electron/He I ultraviolet photoelectron spectra were consistent with the P3 calculation results for ionization of α and β spin electrons except for electron correlation bands observed by PIES. Negative collision energy dependence of partial Penning ionization cross-sections (CEDPICS) indicate attractive interaction with He*(23S) around the molecule. Results by model potential calculation utilizing Li(22S) instead of He*(2 3S) for interaction between He*(23S) and open-shell metallocenes do not explain the strong negative CEDPICS of the bands observed in PIES.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry