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)


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.


Laser Induce Fluorescence Probe Pulse Picosecond Laser Lower Energy Transition Harmonic Pulse 
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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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