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

Abstract

The dissociation of excited species is one of the most important types of chemical reactions, and it has been investigated by using either molecular collision or photon excitation. Mass spectrometry is suited to generate and probe unstable intermediates in the gas phase and has enabled the investigation of the dissociation of various stable and unstable ions. However, investigation of neutral species using this technique has been difficult because of their lack of electronic charge. In this work we have used mass spectrometry to measure collision-induced dissociation (CID) spectra and charge-inversion spectra of CD 3OH + and CH 3OD +. The major dissociation process in CID 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 major process in the photo-induced dissociation of neutral methanol. This demonstrates the usefulness of charge-inversion mass spectrometry as a technique for the investigation of the dissociation of neutral intermediates.