Photoelectron spectra of metallocenes

Abstract The He(II) spectra of the unsubstituted metallocenes {M(η-C 5 H 5 ) 2 }, M  V, Cr, Mn, Fe, Co, Ni and Ru, and of {Mn(η-C 5 H 4 Me) 2 } are reported; both He(I) and He(II) spectra of some decamethylmetallocenes {M(η-C 5 Me 5 ) 2 }, where M  Mg, V, Cr, Mn, Fe, Co and Ni, are also given. Intensity changes between the He(I) and He(II) spectra are shown to provide a reliable guide to band assignment. A ligand field treatment of the decamethylmanganocene cation, including limited configuration interaction, gives values for Δ 2 , B and C ; these values are also in good agreement with the photoelectron spectra of {M(η-C 5 Me 5 ) 2 } where M  V, Cr and Fe. Overlap between the ligand and metal “ d ” band structures prevents complete assignment in the cases of Co and Ni.