Abstract
Gas-phase fast atom bombardment (GFAB) mass spectra of the chromium hexacarbonyl molecule were compared with its charge-exchange ionization (CEI) mass spectra. It was found that the fragmentation pattern of chromium hexacarbonyl ions obtained by He-CEI mass spectrometry most resembles those measured in GFAB, and so it seems that energy deposition during GFAB implies involvement of a resonance-like energy transfer from fast atoms and may be similar or higher than that in He-CEI reaction. No great difference was observed in GFAB mass spectrum for a variety of fast bombarding particles including He, Ar, Xe, Cs, and isobutane. A high pressure GFAB mass spectrum of trolox measured using a Cs beam demonstrated its reactive nature that exchange reaction between hydroxy protons and Cs+ ions seems to take place in gas phase for the molecule and its neutral fragments while a Cs-FAB mass spectrum measured under a relatively low sample gas pressure showed only a fragmentation pattern characterized by a high abundance of fragment ions. Since Cs is only an alkali metal among fast bombarding particles, its chemical nature may be responsible for the observed reactivity with the target molecule.
