University of Illinois Urbana-Champaign

Short-lived Electronically-excited Diatomic Molecules Cooled Via Supersonic Expansion From A Plasma Microjet

Houlahan, Thomas J., Jr.

Content Files
MH13_Abstract.pdf
MH13_Abstract.txt
MH13_Presentation.pdf

Permalink

https://hdl.handle.net/2142/50818

Description

Title
Short-lived Electronically-excited Diatomic Molecules Cooled Via Supersonic Expansion From A Plasma Microjet
Author(s)
Houlahan, Thomas J., Jr.
Contributor(s)
  • Eden, Gary
  • Su, Rui
Issue Date
2014-06-16
Keyword(s)
Mini-symposium: Spectroscopy in Kinetics and Dynamics
Date of Ingest
  • 2014-09-17T16:55:02Z
  • 2015-04-14T18:40:40Z
Abstract
Using a pulsed plasma microjet to generate short-lived, electronically-excited diatomic molecules, and subsequently ejecting them into vacuum to cool via supersonic expansion, we are able to monitor the cooling of molecules having radiative lifetimes as low as 16 ns. Specifically, we report on the rotational cooling of He$_2$ molecules in the $d^3\Sigma_u^+$, $e^3\Pi_g$, and $f^3\Sigma_u^+$ states, which have lifetimes of 25 ns, 67 ns, and 16 ns, respectively. The plasma microjet is driven with a 2.6 kV, 140 ns high-voltage pulse (risetime of 20 ns) which, when combined with a high-speed optical imaging system, allows the nonequilibrium rotational distribution for these molecular states to be monitored as they cool from ~1200 K to below 250 K with spatial and temporal resolutions of below 10 $\mu$m and 10 ns, respectively. The spatial and temporal resolution afforded by this system also allows the observation of excitation transfer between the $f^3\Sigma_u^+$ state and the lower lying $d^3\Sigma_u^+$ and $e^3\Pi_g$ states. The extension of this method to other electronically excited diatomics with excitation energies $>$5 eV will also be discussed.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
text
Genre of Resource
Conference Paper / Presentation
Language
English
Permalink
http://hdl.handle.net/2142/50818
DOI
https://doi.org/10.15278/isms.2014.MH13
Copyright and License Information
Copyright 2014 by the authors. Licensed under a Creative Commons Attribution 4.0 International License. http://creativecommons.org/licenses/by/4.0/

Owning Collections

Abstracts & Presentations - 2014 International Symposium on Molecular Spectroscopy PRIMARY