Dissociative Electron Attachment to Jet Cooled Oxygen

Ramaprasad, Varun (2019) Dissociative Electron Attachment to Jet Cooled Oxygen. Masters thesis, Indian Institute of Science Education and Research Kolkata.

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We have studied the electron attachment process with isolated oxygen molecules and small van der Waals clusters of oxygen formed in pulsed supersonic jet of oxygen molecules. Electron capture by an effusive oxygen beam is known to produce a resonance at 6.5 eV incident electron energy following the reaction.In our study, we have a clear observation of two distinct resonance peaks at ~11 and ~16 eV incident electron energies along with the 6 eV peak, from O⁻ and O₂⁻ ions formed by dissociative electron attachment to a pulsed supersonic jet of O₂ molecules seeded in a beam of argon containing (O2)n clusters Our supersonic expansion setup used for the experiment reduces the cost of the experiement by avoiding a catcher chamber and an extra pump at the orifice, which was otherwise essential in all previous experiments. Formation of small oxygen clusters in such a setup is reported here for the first time. The characteristics of the molecular jet can be completely explained if we know the translational beam temperature and the Mach number. By converting the time-of-flight spectra to a velocity distribution, and fitting this velocity distribution with the equation governing supersonic jets, we can obtain both T and M. In this thesis, we have demostrated this excercise for O⁻ ions in a jet of O₂ with O₂:Ar ratio 1:10. The same analysis can be extended to different ratios and our results provide further impetus to study the same

Item Type: Thesis (Masters)
Additional Information: Supervisor: Dhananjay Nandi
Uncontrolled Keywords: Dissociative Electron Attachment; Electron-molecule Collisions; Jet Cooled Oxygen; Supersonic Expansion .
Subjects: Q Science > QC Physics
Divisions: Department of Physical Sciences
Depositing User: IISER Kolkata Librarian
Date Deposited: 10 Oct 2019 11:41
Last Modified: 10 Oct 2019 11:41
URI: http://eprints.iiserkol.ac.in/id/eprint/867

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