Xenon-Sensitized Fluorescence of CO Excited by 1470-Å Radiation

Abstract

The triplet fluorescence of CO, sensitized by xenon and excited by 1470‐Å radiation, has been investigated. As opposed to unsensitized fluorescence, where almost all the observed triplet emission is from the d 3 Δ υ = 7 state, emission is observed from various vibrational levels of the d 3 Δ, e 3 Σ, and a′ 3 Σ states. It is shown that Xe metastable atoms are not involved in the collisional process that causes excitation, and therefore, a reaction between the resonant Xe ( 3 P 1 ) atom and CO must be occurring. Experiments carried out to compare the quenching of unsensitized and sensitized fluorescence by He, Ar, and N2 indicate that there is a precursor to the emitting CO* in the sensitized case, presumably a collision complex of Xe ( 3 P 1 ) and CO. The reaction Xe* + CO→XeCO appears to take place at every collision, and the complex has a lifetime of at least 2 × 10−6 sec before it decomposes to Xe and CO*. Rate constants were obtained for the quenching of CO* by various gases, including CO, and ratios of rate constants were found for XeCO quenching by He, Ar, N2, and CO.