eprintid: 7259 rev_number: 5 userid: 6 dir: disk0/00/00/72/59 datestamp: 2011-11-10 19:38:08 lastmod: 2016-11-15 13:40:44 status_changed: 2011-11-10 19:38:08 type: thesis_degree metadata_visibility: show contact_email: cetme50@hotmail.com item_issues_count: 0 eprint_status: archive creators_name: Noroski, Joseph H. creators_email: cetme50@hotmail.com title: COLLISION ENERGY DEPENDENCE OF THE REACTIONS OF METASTABLE NEON WITH SMALL MOLECULES ispublished: unpub divisions: sch_as_chemistry full_text_status: public keywords: autoionization; electron spectroscopy; metastable neon; molecular collisions; Penning ionization; reaction dynamics abstract: The reaction dynamics of Ne* (2p⁵3s³P₂, ³P₀) + X → [NeX]⁺ + e⁻(X = H₂, CO, N₂, NO, O₂, CO₂, and C₂H₂) were studied with supersonic beams at various collision energies (E) via electron spectroscopy. Increasing E decreases the interparticle distance at which ionization occurs, allowing for exploration of the reaction potential energy surfaces via the kinetic energy ε of the ejected electron. Data were fit to give vibrational populations and line shifts (Δεs), the difference between the excitation energy of Ne* and the vibronic energy of the target molecules, where vibronic excitation is due to Ne*. The resulting populations were compared to calculated or experimental Franck-Condon factors (FCfs), and vibrational progressions were identified. Deviation from Franck-Condon (FC) behavior was observed in all cases except for C₂H₂, and all spectra at all E showed a blue shift except CO₂. With increasing E, Δεs for H₂⁺, CO⁺, and N₂⁺ increased with increasing E, while Δεs decreased for NO⁺ and C₂H₂⁺. The CO2⁺ spectra revealed a nearly constant red shift for the lowest three E and a blue shift for the highest E. O₂⁺ showed a very small blue shift, but the O₂⁺ populations were not determined due to an underlying continuum. Penning, excitation transfer, and ion-pair mechanisms are the most widely accepted for the reactions of metastable atoms. The closed-shell structure of H₂, CO, and N₂ and the large, increasing Δεs suggest that their Ne* reactions proceed via the Penning mechanism. The open- shell structure of NO and its decreasing Δεs indicates changing dynamics and possibly also competition between all three mechanisms for Ne* + NO. The very small Δεs for O₂⁺ implies the excitation transfer mechanism for Ne* + O₂. Ne* reactions with CO₂ and C₂H₂ both exhibited constant Δεs values for more than one E. This suggests that an excitation transfer mechanism is at work in these systems, but changes in Δεs at other E indicate that competing mechanisms may also be relevant. Lastly, a retrospective on authoring a solutions manual for a freshman chemistry textbook is offered. date: 2009-06-17 date_type: completed institution: University of Pittsburgh refereed: TRUE etdcommittee_type: committee_chair etdcommittee_type: committee_member etdcommittee_type: committee_member etdcommittee_type: committee_member etdcommittee_name: Jordan, Kenneth D etdcommittee_name: Pratt, David W etdcommittee_name: Hutchison, Geoff etdcommittee_name: Mueller, James etdcommittee_email: ken@visual1.chem.pitt.edu etdcommittee_email: pratt@pitt.edu etdcommittee_email: geoffh@pitt.edu etdcommittee_email: mueller@pitt.edu etdcommittee_id: JORDAN etdcommittee_id: PRATT etdcommittee_id: GEOFFH etdcommittee_id: MUELLER etd_defense_date: 2009-04-03 etd_approval_date: 2009-06-17 etd_submission_date: 2009-04-17 etd_access_restriction: immediate etd_patent_pending: FALSE assigned_doi: doi:10.5195/pitt.etd.2011.7259 thesis_type: dissertation degree: PhD committee: Kenneth D. Jordan (ken@visual1.chem.pitt.edu) - Committee Chair committee: David W. Pratt (pratt@pitt.edu) - Committee Member committee: Geoff Hutchison (geoffh@pitt.edu) - Committee Member committee: James Mueller (mueller@pitt.edu) - Committee Member etdurn: etd-04172009-114939 other_id: http://etd.library.pitt.edu/ETD/available/etd-04172009-114939/ other_id: etd-04172009-114939 citation: Noroski, Joseph H. (2009) COLLISION ENERGY DEPENDENCE OF THE REACTIONS OF METASTABLE NEON WITH SMALL MOLECULES. Doctoral Dissertation, University of Pittsburgh. (Unpublished) document_url: http://d-scholarship-dev.library.pitt.edu/7259/1/NOROSKI_APR2009_PCHEM.pdf