Accession Number : ADA326698

Title :   Unusual Laser Excitations (5,890-6,520 A) of the B2 sigma(+) Electronic State of CN in an Atmospheric-Pressure Flame.

Descriptive Note : Final rept. Jan 90-Dec 96,

Corporate Author : ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD

Personal Author(s) : Guthrie, J. A. ; Bowen, T. S. ; Anderson, W. R. ; Kotlar, A. J. ; Bunte, S. W.

PDF Url : ADA326698

Report Date : JUN 1997

Pagination or Media Count : 76

Abstract : The CN radical plays an important role in the chemistry of nitramine propellant flames. Diagnostic methods for detection of this radical are therefore important for studies of its role in propellant combustion experiments. In this work, CN laser induced fluorescence (LIF) in an atmospheric pressure flame was studied. The first such flame study involving observation of LIF in the strong CN B-X violet system, near 3880 A, but with excitation using strong, fundamental dye laser outputs, near 6000 A, is reported. Excitation at significantly longer wavelengths (smaller photon energy) than LIF observation wavelengths is unusual. Because the high intensity fundamental outputs of dye lasers may be used, these excitations could ultimately prove to be very effective diagnostic methods for this species. Subsequent investigation of the spectra has revealed that at least four distinct excitation processes, some of which involve molecular collisions, are responsible for the observed LIF as the laser is scanned in this region. The observed spectra reveal some of the unexpected effects of collisions and laser intensity on absorption and fluorescence in this molecule.

Descriptors :   *LASER INDUCED FLUORESCENCE, *COMBUSTION, ENERGY TRANSFER, LASER BEAMS, PROPELLANTS, ELECTRONIC STATES, PHOTONS, CYANIDES, MOLECULE MOLECULE INTERACTIONS, DYE LASERS, HIGH INTENSITY, FLAMES, BAROMETRIC PRESSURE, ELECTRON TRANSITIONS, NITRAMINES.

Subject Categories : Lasers and Masers
      Atomic and Molecular Physics and Spectroscopy
      Combustion and Ignition

Distribution Statement : APPROVED FOR PUBLIC RELEASE