Guided ion-beam studies of the reactions of Fen+ (n=1–18) with CO2: Iron cluster oxide bond energies

The kinetic energy dependence of the reactions of Fen+ (n=1–18) with CO2 are studied in a guided ion-beam mass spectrometer. The primary product ions are FenO+, which then decompose by sequential loss of iron atoms as the kinetic energy is increased. Simple collision-induced dissociation to form the Fen−1+ product ions is also observed. Large cluster ions, n⩾9, form the FenCO2+ adduct at low kinetic energies. The cross section for the primary reaction, Fen++CO2→FenO++CO, exhibits an interesting bimodal energy behavior that is discussed in some detail. Fen+–O bond energies are measured and found to compare well with previous measurements obtained from guided ion-beam studies of the Fen++O2 systems. The trends in this thermochemistry are discussed and compared to bulk phase values.