Journal Article

FZJ-2017-05232

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Temperature dependence of stable carbon kinetic isotope effect for the oxidation reaction of ethane by OH radicals: experimental and theoretical studies

Piansawan, T.FZJ* ; Saccon, M. ; Vereecken, L. (Corresponding author)FZJ* ; Gensch, I. (Corresponding author)FZJ* ; Kiendler-Scharr, A.FZJ*

2017
Wiley Hoboken, NJ

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Please use a persistent id in citations: http://hdl.handle.net/2128/16025  doi:10.1002/2017JD026950

Abstract: The stable carbon kinetic isotope effect (KIE) of ethane photooxidation by OH radicals was deduced by employing both laboratory measurements and theoretical calculations. The investigations were designed to elucidate the temperature dependence of KIE within atmospherically relevant temperature range. The experimental KIE was derived from laboratory compound-specific isotope analyses of ethane with natural isotopic abundance exposed to OH at constant temperature, showing ε values of 7.16 ± 0.54‰ (303 K), 7.45 ± 0.48‰ (288 K), 7.36 ± 0.28‰ (273 K), 7.61 ± 0.28‰ (263 K), 8.89 ± 0.90‰ (253 K), and 9.42 ± 2.19‰ (243 K). Compared to previous studies, a significant improvement of the measurement precision was reached at the high end of the investigated temperature range. The KIE was theoretically determined as well, in the temperature range of 150 K to 400 K, by calculating the reaction rate coefficients of 12C and singly 13C substituted ethane isotopologues applying chemical quantum mechanics together with transition state theory. Tunneling effect and internal rotations were also considered. The agreement between experimental and theoretical results for rate coefficients and KIE in an atmospherically relevant temperature range is discussed. However, both laboratory observations and computational predictions show no significant temperature dependence of the KIE for the ethane oxidation by OH radicals.

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Contributing Institute(s):

1. Troposphäre (IEK-8)

Research Program(s):

1. 243 - Tropospheric trace substances and their transformation processes (POF3-243) (POF3-243)

Appears in the scientific report 2017

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Database coverage:
; ; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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