Mass-selected infrared photodissociation spectroscopy of V4O10+

The gas-phase infrared spectroscopy of V4O10+ produced by laser vaporization has been studied in the spectral region from 7 to 16 mum. Mass-selected V4O10+ cations were stored in a helium filled radio frequency hexadecapole ion trap and excited using tunable infrared radiation from a free electron laser. The photodissociation spectrum was recorded by monitoring the V4O8+ yield (O-2 loss) as a function of the excitation wavelength. Two absorption bands at 842 and 1032 cm(-1) are observed, which are assigned to resonant excitation of the antisymmetric V-O-V stretching and V=O stretching vibrations, respectively. Comparison to recent theoretical and experimental studies indicate that the absorbing species consists of a V4O8+ ionic core weakly bound to an oxygen molecule.