Termolecular rate coefficients and the standard enthalpy of the reaction OH + CS2 + M → HOCS2 + M

Wei-Guang Diau, Yuan-Pern Lee*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

The reaction between OH and CS2 has been studied in He in the pressure range 9-270 Torr and the temperature range 249-298 K by means of the laser-photolysis/laser-induced-fluorescence technique. Analysis of the temporal profile of [OH] yielded the rate coefficients for the forward and reverse reactions for the equilibrium OH + CS2 + ⇌ HOCS2 + M and hence the equilibrium constant. Study of the temperature dependence of the equilibrium constant leads to the standard enthalpy of reaction ΔH° = -43.9 ± 5.3 kJ mol-1 and the standard entropy of reaction ΔS° = -102.9 ± 15.4 J K-1 mol-1. The termolecular rate coefficients for the forward reaction at 298 K have also been determined to be kHe III = (5.04 ± 1.01) × 10-32 cm6 molecule-2 s-1 and kCS2 III = (4.28 ± 1.07) × 10-31 cm6 molecule-2 s-1. The rate coefficients for the reverse reaction at 298 K have been determined to be kHe R = (7.36 ± 1.47) × 10-15 cm3 molecule-1 s-1 and kCS2 R = (5.79 ± 1.45) × 10-14 cm3 molecule-1 s-1. All uncertainties represent 95% confidence limits. The temperature dependence of kHe III and kHe R corresponds to activation energies Ea = -13.4 ± 3.4 and 34.6 ± 8.7 kJ mol-1, respectively. For the reaction also studied in Ar at 246 K, consistent results have been obtained.

Original languageEnglish
Pages (from-to)379-386
Number of pages8
JournalJournal of Physical Chemistry
Volume95
Issue number1
DOIs
StatePublished - 1 Dec 1991

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