A new technique to study the dissociation of energy-selected neutral intermediates

The dissociation of excited species is one of the most important types of c hemical reactions, and it has been investigated by using either molecular c ollision or photon excitation. Mass spectrometry is suited to generate and probe unstable intermediates in the gas phase and has enabled the investiga tion of the dissociation of various stable and unstable ions. However, inve stigation of neutral species using this technique has been difficult becaus e of their lack of electronic charge. In this work we have used mass spectr ometry to measure collision-induced dissociation (CID) spectra and charge-i nversion spectra of CD3OH+ and CH3OD+. The major dissociation process in CI D was found to involve elimination of a hydrogen atom from the methyl group , whereas dissociation in the charge-inversion mass spectrometer was found to be via elimination of a hydrogen atom from the hydroxyl group. Hydrogen atom elimination from the hydroxyl group has also been reported as the majo r process in the photo-induced dissociation of neutral methanol. This demon strates the usefulness of charge-inversion mass spectrometry as a technique for the investigation of the dissociation of neutral intermediates. (Int J Mass Spectrom 202 (2000) A1-A7) (C) 2000 Elsevier Science B.V.