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Picosecond Laser Induced Fluorescence Probing of NO2 Photofragments

  • P. E. Schoen
  • M. J. Marrone
  • L. S. Goldberg
Conference paper
Part of the Springer Series in Chemical Physics book series (CHEMICAL, volume 23)

Abstract

The UV photolysis of nitromethane has been studied extensively for many years [1–12]. It is now generally accepted that the primary photodissociation process leads to formation of the free radicals CH3 and NO2 in the reaction: \( CH_3 NO_2 \xrightarrow{{h\nu }}CH_3 + NO_2 \) We have performed 264 nm photolysis of nitromethane in the gas phase and have observed formation of ground-state NO2 product within the 5 ps pulse resolution time of our laser. This represents the first direct observation of the initial fragments of nitromethane photodecomposition with picosecond time resolution. We have employed a newly developed Nd:phosphate glass laser system, mode-locked and repetitively pulsed at 0.2 Hz [13]. The presence of NO2 radicals was probed by its fluorescence induced with a second harmonic pulse at 527 nm. Thus using picosecond-delayed laser induced fluorescence (LIF) in the gas phase (0.1 to 10 Torr), we have been able to observe ground-state product formation in the collision free regime. The technique of exciting fragment molecules to a fluorescent state has proved to be a particularly well adapted approach to detecting gas phase species at low concentrations.

Keywords

Laser Induce Fluorescence Probe Pulse Picosecond Laser Lower Energy Transition Harmonic Pulse 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1982

Authors and Affiliations

  • P. E. Schoen
    • 1
  • M. J. Marrone
    • 1
  • L. S. Goldberg
    • 1
  1. 1.Naval Research LaboratoryUSA

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