Reaction of F Atoms with Carbonyl Sulfide: Experimental and Theoretical Study

Abstract

The gas phase reaction of fluorine atoms with carbonyl sulfide, F + OCS → SF + CO (1), has been investigated over a wide temperature range, T = 220–960 K, in a discharge-flow system combined with mass spectrometry for the analysis of the reactive mixture. The reaction rate coefficient was determined as a function of temperature using both absolute (under pseudo-first-order conditions using an excess of F atoms) and relative rate methods: k1 = (8.95 ± 0.52) × 10−11 exp((102 ± 20)/T) cm3 molecule−1 s−1 (with an estimated total uncertainty of 15% independent of temperature). The SF radical was observed as the main primary reaction product. The experimental results are supported by theoretical calculations, which evidence that the reaction is exothermic with a weak negative temperature dependence.

Keywords

• fluorine atom
• carbonyl sulfide
• rate coefficient
• temperature dependence
• negative activation energy