Collisional quenching of CO B {sup 1}{sigma}{sup +}(v{sup '}=0) probed by two-photon laser-induced fluorescence using a picosecond laser
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551 (United States)
We report measurements of room-temperature, species-specific quenching cross sections of CO B {sup 1}{sigma}{sup +} (v{sup '}=0) in collisions with He, Ne, H{sub 2}, N{sub 2}, Ar, CO, Kr, CH{sub 4}, O{sub 2}, Xe, CO{sub 2}, C{sub 3}H{sub 8}, and H{sub 2}O. The measured quenching cross sections (in Aa2) were 0.25{+-}0.02, 0.54{+-}0.04, 11.0{+-}0.4, 24.6{+-}0.5, 27.7{+-}0.5, 37{+-}2, 42{+-}2, 81{+-}4, 85{+-}5, 99{+-}6, 133{+-}5, 144{+-}7, and 170{+-}8, respectively. Two-photon excitation of the CO molecules via the Hopfield-Birge system (X {sup 1}{sigma}{sup +}{yields}{yields}B {sup 1}{sigma}{sup +}) was performed using the frequency-tripled 690 nm emission of a custom-built picosecond dye laser. Blue-to-green fluorescence in the Angstroem bands (B {sup 1}{sigma}{sup +}{yields}A {sup 1}{pi}) was detected using a microchannel-plate photomultiplier tube and recorded with a digital storage oscilloscope. The quenching cross sections were directly obtained by time resolving the temporal decay of the fluorescence signal and observing its variation as a function of the quencher pressure. The effect of radiative trapping on the observed fluorescence was also quantitatively modeled. (c) 2000 American Institute of Physics.
- OSTI ID:
- 20217328
- Journal Information:
- Journal of Chemical Physics, Vol. 113, Issue 8; Other Information: PBD: 22 Aug 2000; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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