Kinetic study of electronically excited atoms, I(52P½) in the presence of olefines
- 1 January 1969
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Transactions of the Faraday Society
- Vol. 65, 2941-2947
- https://doi.org/10.1039/tf9696502941
Abstract
The decay of electronically excited iodine atoms, I(52P½), in the presence of a number of olefines has been studied by kinetic absorption spectroscopy in the ultra-violet and the vacuum ultra-violet. The mode of removal is dominated by collisionally induced spin orbit relaxation to the I(52P) ground state rather than by chemical reaction. The second-order rate constants for electronic quenching by the molecules ethylene, propylene, 1-butene, trans-butene-2, cis-butene-2, isobutene, tetramethylethylene, C2F4 and C2F3H are 7.0 × 10–14, 1.6 × 10–13, 1.6 × 10–13, 2.1 × 10–13, 2.2 × 10–13, 3.0 × 10–13, 6.3 × 10–13, 3.7 × 10–15 and 5.3 × 10–14 cm3 molecule–1 s–1, respectively. For the hydrocarbon olefines, these rate constants correlate with ionization potential, excitation energy of the π—π* transition and heat of hydrogenation. Thus, on collision, a charge-transfer interaction with the π electrons of the olefine is involved, leading to relaxation.Keywords
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