Collisional quenching of singlet molecular oxygen, O2(a 1? g ) and O2(b 1? + g ), by ammonia at high temperatures
- 1 January 1984
- 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. 80 (7) , 817-822
- https://doi.org/10.1039/f29848000817
Abstract
The discharge-flow/shock-tube technique has been used to measure the temperature dependence of the collisional quenching of singlet molecular oxygen, O2(b1Σ+ g) and O2(a1Δg), by NH3 between 600 and 1150 K. For the quenching of O2(b1Σ+ g) by NH3, the rate constant at 295 K is (7.50 ± 0.10)× 108 dm3 mol–1 s–1. The rate constant is found to be independent of temperature between 210 and ca. 750 K; above 750 K the value falls slowly to 2.5 × 108 dm3 mol–1 s–1 at 1150 K. Thus NH3 fits the pattern of efficient quenchers of O2(b1Σ+ g). In this work the analysis method has been modified to allow for efficient quenchers and the new approach has allowed us to verify the analysis used previously. The rate constant for the quenching of O2(a1Δg) by NH3 was too slow at high temperatures to measure within the timescale of our experiment. The value at 295 K is (5.37 ± 0.14)× 103 dm3 mol–1 s–1 and the upper limit at 1150 K is 1.3 × 104 dm3 mol–1 s–1.Keywords
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