Electronic transitions of protonated Benzene and Fulvene, and C6H7 isomers in neon matrices

Electronic transitions of protonated benzene (Ã 1B2←X̃ 1A1, origin at 325 nm) and α-protonated fulvene (Ã 1A′←X̃ 1A′, at 335 nm) trapped in 6 K neon matrices have been detected. The cations were produced from several different precursors, mass-selected, and co-deposited with neon. After neutralization of the cations, the electronic transitions of cyclohexadienyl (onsets at 549 and 310 nm) and α-hydrogenated fulvene (532 and 326 nm) radicals were identified. Upon excitation of cyclohexadienyl to the B̃ 2B1 state, photoisomerization to an open-chain structure and α-hydrogenated fulvene was observed.