Link to the University of Pittsburgh Homepage
Link to the University Library System Homepage Link to the Contact Us Form

COLLISION ENERGY DEPENDENCE OF THE REACTIONS OF METASTABLE NEON WITH SMALL MOLECULES

Noroski, Joseph H. (2009) COLLISION ENERGY DEPENDENCE OF THE REACTIONS OF METASTABLE NEON WITH SMALL MOLECULES. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

[img]
Preview
PDF
Primary Text

Download (2MB) | Preview

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.


Share

Citation/Export:
Social Networking:
Share |

Details

Item Type: University of Pittsburgh ETD
Status: Unpublished
Creators/Authors:
CreatorsEmailPitt UsernameORCID
Noroski, Joseph H.cetme50@hotmail.com
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairJordan, Kenneth Dken@visual1.chem.pitt.eduJORDAN
Committee MemberPratt, David Wpratt@pitt.eduPRATT
Committee MemberHutchison, Geoffgeoffh@pitt.eduGEOFFH
Committee MemberMueller, Jamesmueller@pitt.eduMUELLER
Date: 17 June 2009
Date Type: Completion
Defense Date: 3 April 2009
Approval Date: 17 June 2009
Submission Date: 17 April 2009
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Chemistry
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: autoionization; electron spectroscopy; metastable neon; molecular collisions; Penning ionization; reaction dynamics
Other ID: http://etd.library.pitt.edu/ETD/available/etd-04172009-114939/, etd-04172009-114939
Date Deposited: 10 Nov 2011 19:38
Last Modified: 15 Nov 2016 13:40
URI: http://d-scholarship.pitt.edu/id/eprint/7259

Metrics

Monthly Views for the past 3 years

Plum Analytics


Actions (login required)

View Item View Item