Isotope Effect in the Carbonyl Sulfide Reaction with O(3P)

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• 作者：Shohei Hattori ; Johan A. Schmidt ; Denise W. Mahler ; Sebastian O. Danielache ; Matthew S. Johnson ; Naohiro Yoshida
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：April 12, 2012
• 年：2012
• 卷：116
• 期：14
• 页码：3521-3526
• 全文大小：275K
• 年卷期：v.116,no.14(April 12, 2012)
• ISSN：1520-5215

文摘

The sulfur kinetic isotope effect (KIE) in the reaction of carbonyl sulfide (OCS) with O(³P) was studied in relative rate experiments at 298 卤 2 K and 955 卤 10 mbar. The reaction was carried out in a photochemical reactor using long path FTIR detection, and data were analyzed using a nonlinear least-squares spectral fitting procedure with line parameters from the HITRAN database. The ratio of the rate of the reaction of OC³⁴S relative to OC³²S was found to be 0.9783 卤 0.0062 (³⁴蔚 = (鈭?1.7 卤 6.2)鈥?. The KIE was also calculated using quantum chemistry and classical transition state theory; at 300 K, the isotopic fractionation was found to be ³⁴蔚 = 鈭?4.8鈥? The OCS sink reaction with O(³P) cannot explain the large fractionation in ³⁴S, over +73鈥? indicated by remote sensing data. In addition, ³⁴蔚 in OCS photolysis and OH oxidation are not larger than 10鈥? indicating that, on the basis of isotopic analysis, OCS is an acceptable source of background stratospheric sulfate aerosol.