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Diode laser probing of the low frequency vibrational modes of baths of CO sub 2 and N sub 2 O excited by relaxation of highly excited NO sub 2

Journal Article · · Journal of Chemical Physics; (USA)
DOI:https://doi.org/10.1063/1.459286· OSTI ID:5989578
; ; ;  [1]
  1. Department of Chemistry, Columbia University, New York, NY (USA) Columbia Radiation Laboratory, Columbia University, New York, NY (USA)
Quenching of highly excited vibrational states of NO{sub 2} in baths of CO{sub 2} and N{sub 2}O has been investigated. Dilute NO{sub 2} mixtures were excited by a pulse from an excimer pumped dye laser operating at 495 nm. Various vibrational modes of the bath gases were probed with continuous wave IR diode lasers. Less than 20% of the energy initially placed in the NO{sub 2} by the dye laser is taken up by the vibrational degrees of freedom of the CO{sub 2} or N{sub 2}O baths. For N{sub 2}O, the three different vibrational modes ({nu}{sub 1}=1285 cm{sup {minus}1}, {nu}{sub 2}=589 cm{sup {minus}1}, {nu}{sub 3}=2223 cm{sup {minus}1}) take up almost equal amounts of energy from NO{sub 2}, but the number of vibrational quanta produced in the bath is found to increase with decreasing vibrational frequency. Similar results are found for CO{sub 2} except that the {nu}{sub 1} and {nu}{sub 2} modes cannot be studied separately for this bath gas due to rapid {nu}{sub 1}{leftrightarrow}{nu}{sub 2} intermode equilibration.
DOE Contract Number:
FG02-88ER13937
OSTI ID:
5989578
Journal Information:
Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 93:12; ISSN JCPSA; ISSN 0021-9606
Country of Publication:
United States
Language:
English