Quenching of laser-excited O2(b 1Σ+g) by CO2, H2O, and I2

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Abstract
The total quenching rates of O2(b 1Σ+g) by CO2, H2O, and I2 have been determined to be (4.53±0.29)×10−13 cm3 molec−1 sec−1, (6.71±0.53)×10−12 cm3 molec−1 sec−1, and (2.04±0.28)×10−11 cm3 molec−1 sec−1, respectively. A pulsed, Raman‐shifted dye laser was used to excite a single rotational line of O2(1Σ, v′=0), while subsequent 1Σ→3Σ fluorescence was monitored by a photon counting technique to determine the deactivation rate as a function of the partial pressure of quenching gas. Rate constants for deactivation of O2(1Σ) by CO2 and H2O were found to be consistent with those measured elsewhere, whereas I2 was found to quench O2(1Σ) an order of magnitude more slowly than reported in the literature. The lower total quenching constant for I2 suggests that the reaction O2(1Σ)+I2→O2(3Σ) +2I might not be responsible for dissociation of I2 in the chemical oxygen‐iodine laser.