DIMERIZATION OF THE KETENE CATION RADICAL IN THE GAS-PHASE

The dimerization of the ketene cation radical was investigated by using tandem mass spectrometry. Ketene was ionized by low-energy charge-exchange with CS2+. reagent ions. The high-pressure environment in the ion source permits collisional stabilization of the ion/molecule adduct, which was characterized by obtaining its collisionally activated dissociation (CAD) mass spectrum. Comparison with the CAD spectrum of diketene+. revealed that the structure of the adduct is identical with that of the ionized diketene species. The singly occupied molecular orbital-lowest unoccupied molecular orbital (SOMO-LUMO) interaction was invoked to explain the formation of the ion/molecule adduct.