Laser-excitation study of triplet CO
- 1 January 1981
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics
- Vol. 77 (8) , 1375-1386
- https://doi.org/10.1039/f29817701375
Abstract
Metastable CO a3Π(v= 0) molecules, at concentrations near 108–109 cm–3, were produced by the reaction Ar3P2,0+CO2→ CO a3Π+ O + Ar. Narrow-band excitation with a dye laser was used to form the d3Δ state of CO, which was observed through fluorescence of the d–a transition. Rotationally-resolved d–a laser-excitation spectra are reported. Lifetime measurements of the d3Δ state were made from fluorescence decays, following initial excitation of the v= 5 and 4 vibrational levels. The zero-pressure lifetime of CO d3Δ(v= 4) was 5.75 ± 0.70 µs. Vibrational relaxation of CO d3Δ(v= 4) in collisions with Ar was found to be efficient, with a probability of ca. 10–2. Relaxation is believed to occur by collisional curve-crossing, probably to the e3Σ– state, rather than by V–T transfer. Lifetime data on d3Δ(v= 5) support the existence of a strong, rotationally-dependent perturbation in the Ω= 1 component of this state.Keywords
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