Collisional Detachment of Anions using Fourier Transform Mass Spectrometry
Abstract
Fourier Transform Mass Spectrometry (FTMS) is used to make energy resolved ion-neutral reaction measurements at high translational energies (up to several hundred eV). The technique is demonstrated for collisional detachment of anions, and should be easily applied to other inelastic reactions. Collisional detachment cross sections of iodine anions onto gas phase targets of neon, xenon, and trifluoromethyl iodide are measured for 1-300 eV (lab frame). Peak detachment cross sections are roughly 2, 8.5, and 7 square angstroms, respectively. Ion kinetic measurements show the iodine anion is unreactive in trifluoromethyl iodide at thermal energies. Positive ion chemistry is consistent with previous results from well established techniques. However, the influence of internal energy is quantified for the first time by varying the electron energy of ion formation. Changes in the observed reactions of iodine cations and trifluoromethyl iodide cations are attributed to ion formation in excited states. Ionization and attachment cross sections for electron impact on trifluoromethyl iodide are reported for the first time over the energy range 10- 50 eV. The ion motion in the FTMS ion trap is modelled and the relationship between the ion trajectory and the ion image current is quantified.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1992
- Accession Number
- ADA258972
Entities
People
- Kevin B. Riehl
Organizations
- Air Force Institute of Technology