Reactivity of Highly Excited Diatomic Ions in Hypersonic Nonequilibrium Flow Conditions

Abstract

During this funding cycle, we have constructed and successfully integrated a state-of-the-art guided-ion beam mass spectrometer into the high-resolution photoion-photoelectron apparatus (Endstation 2) of the Chemical Dynamics Beamline at the Advanced Light Source (ALS) for the study of ion-molecule reaction dynamics. Preliminary tests on the performance of this guided-ion beam mass spectrometer have been made, indicating that the ion-molecule reactio photoionization apparatus is performing well. We have also obtained preliminary results on the collision-induced dissociation (CID) and charge transfer (CT) cross sections for the reactions of O2 + (v + = 0-3) + Ar. We have also completed the analysis of the rotationally resolved pulsed field ionization (PFI)-photoelectron (PFI-PE) spectra for the formation of O2+(X2II3/2, 1/2g; v + =0-38), O2+(a4II5/2,3/2,1/2,-1/2u), O2+(A2113/2,1/2u, v+ =0-12), NO+(X'E+, v+ =0-32), and NO+(A'E-,v+ =0-17). The information thus obtained about these states will be needed for ion internal state-selections of O2 + and NO +. A synchrotron-based PFI-photoion (PFI-PI) detection scheme was demonstrated for rovibronic-state selection of 112+. This method is equivalent to the PFI-PE-photoion coincidence (PFI-PEPICO) method and is potentially useful for internal state-selection of reactant ions. In order for this PFI-PI scheme to be applicable to state-selections of heavier ions, such as O2 + , N2 +, and NO +, it is necessary to increase the dark gap of the synchrotron ring period to = 1 us. This can be accomplished by using a slotted chopper wheel to chop the synchrotron beam. Using an electron impact ionization source, we have also examined the CID and CT channels of the O2+(X2113/1,1/2g;v+) + Ar (Ne) reactions.

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Document Details

Document Type
Technical Report
Publication Date
Oct 23, 2002
Accession Number
ADA408719

Entities

People

  • Cheuk-yiu Ng
  • Rainer A. Dressler

Organizations

  • Iowa State University

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Air Force Research Laboratories
  • Charge Transfer
  • Chemical Kinetics
  • Collisions
  • Detection
  • Dissociation
  • Electrons
  • High Resolution
  • Ion Beams
  • Ionization
  • Mass Spectrometers
  • Nonequilibrium Flow
  • Photoelectrons
  • Photoionization
  • Spectra
  • Spectrometers
  • Spin-Orbit Interaction

Fields of Study

  • Physics

Readers

  • Molecular Photonics/Laser Physics

Technology Areas

  • Hypersonics
  • Hypersonics - Hypersonic Flight
  • Microelectronics