University of Illinois Urbana-Champaign

Spectroscopic Studies Of Small Polyatomic Molecules Near Ion-pair Dissociation Thresholds

Kreis, Carla

Content Files
5679.pdf
RL12_5679.pdf

Permalink

https://hdl.handle.net/2142/111486

Description

Title
Spectroscopic Studies Of Small Polyatomic Molecules Near Ion-pair Dissociation Thresholds
Author(s)
Kreis, Carla
Contributor(s)
  • Merkt, Frédéric
  • Hollenstein, Urs
Issue Date
2021-06-24
Keyword(s)
Electronic structure, potential energy surfaces
Date of Ingest
  • 2021-09-24T21:09:52Z
  • 2022-01-21T16:09:46Z
Abstract
At high vibrational quantum numbers, ion-pair states (A$^+$--B$^-$) behave like high Rydberg states. Their level structure can be approximately described by Rydberg's formula after replacing the Rydberg constant $R_{\infty}$ by the appropriate mass-scaled value $R_{IP}=R_{\infty} \frac{\mu_{A^+-B^-}}{m_e}$.\footnote{E. Reinhold and W. Ubachs, Mol. Phys., 103:10, 1329-1352, (2005)} We present the results of spectroscopic investigations of high-lying excited ion-pair states of small polyatomic molecules in the vicinity of ion-pair dissociation thresholds. Such states have been extensively characterized in diatomic molecules (see ref. $^a$$^,$\footnote{S. Mollet, F. Merkt, Phys. Rev. A., 82, 032510, (2010)} and references therein) and are at the heart of the technique of threshold ion-pair production spectroscopy.\footnote{J.D.D. Martin, J.W. Hepburn. Phys. Rev. Lett., 79, 3154, (1997)} Only few studies have been carried out on polyatomic molecules.\footnote{R. C. Shiell, X. K. Hu, Q. J. Hu, J. W. Hepburn, J. Phys. Chem., 104, 19 (2000)}$^,$\footnote{Q. J. Hu, Q. Zhang, J.W. Hepburn. J. Chem. Phys., 123, 074310, (2006)} Polyatomic molecules exhibit denser series of ion-pair dissociation thresholds corresponding to the different rovibrational levels of the positively and negatively charged fragments. We will present the results of our investigations of OCS and H$_2$S in the vicinity of their lowest ion-pair dissociation thresholds. The experiments are carried out using cold samples in skimmed supersonic expansions. The region of the lowest ion-pair dissociation threshold is reached by single-photon excitation from the neutral ground state using narrow-band VUV radiation. The experiments provide access to the ion-pair dissociation energies from which the level structure of the ionic fragments can be determined as well as other thermochemical data such as electron affinities, ionization and dissociation energies.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
Text
Genre of Resource
Conference Paper / Presentation
Language
eng
Permalink
http://hdl.handle.net/2142/111486
DOI
10.15278/isms.2021.RL12

Owning Collections

Abstracts & Presentations - 2021 International Symposium on Molecular Spectroscopy PRIMARY