Raman excitation profiles of C70 in benzene solution. Assignment of the electronic spectrum in the 380 - 510-nm region

The resonance Raman spectrum of C70 was examined in benzene employing 11 laser excitation energies across the main visible absorption band (MVAB) of C70 between 514.5 and 406.7 nm. Three electronic transitions under the MVAB were determined and assigned definitively: the HOMO - 4(e2') -> LUMO + 1 (e1') transition in the 514/501-nm excitation region, the HOMO - 5 (e1') -> LUMO + 1 (e1') transition in the 476/472-nm excitation region and the HOMO (a2') -> LUMO + 2 (a1') in the 457/452-nm excitation region. The REPs indicated that these three electronic transitions are vibronically coupled to the strong electronic transition at 382 nm.