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U.S. Department of Energy
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Collisional (T-V) excitation of CO/sub 2/ molecules by hot H. atoms

Thesis/Dissertation ·
OSTI ID:5528587
193nm photofragmentation of HBr molecules in HBr/CO/sub 2/ mixtures produces energetic (2.5 eV) hydrogen atoms which vibrationally excite CO/sub 2/ molecules via an inelastic translation-vibration/rotation (T-V/R) energy transfer process. Prompt infrared emission in the 4.3..mu..m region has been wavelength resolved, and the spectral energy distribution associated with the excited CO/sub 2/ product was measured. The emission profile is strongly red shifted from the spectral region of the nu/sub 3/ (00/sup 0/1 - 00/sup 0/0) fundamental transition indicating that these energetic collisions preferentially produce combination and overtone levels with oscillator strength in the 4.3..mu..m region. Cold gas filter studies show that significant emission originates from CO/sub 2/ bend-stretch excitation compared to pure stretching excitation. The vibrational energy distribution of the collisionally excited CO/sub 2/ molecules has been measured via time-resolved transient absorption of a diode laser probe beam following 193nm photodissociation of H/sub 2/S molecules in the presence of CO/sub 2/. IR diode laser transient absorption measurements indicate a population increase of 1.29, 1.06, and 67.8 over the ambient population in the nu/sub 1/, nu/sub 2/, and nu/sub 3/ vibrational states of the CO/sub 2/ molecules respectively.
OSTI ID:
5528587
Country of Publication:
United States
Language:
English