Spectroscopic and kinetic study of the gas-phase CS 2[sbnd]Cl adduct

Abstract

Time-resolved UV–vis absorption spectroscopy (TRUVVAS) has been coupled with 248 nm laser flash photolysis (LFP) of Cl 2CO in the presence of CS 2 (and in some cases O 2, NO or NO 2) to generate the CS 2 Cl radical adduct in the gas phase and study the spectroscopy and kinetics of this species. CS 2 Cl is found to possess a strong absorption band at λ max ≈ 365 nm with σ max = (2.3 ± 0.7) × 10 −17 cm 2 molecule −1 (base e) and a weaker band at λ max ≈ 480 nm; the gas-phase spectrum of CS 2 Cl is very similar to the previously reported liquid-phase spectrum in CCl 4 solvent. Reaction of CS 2 Cl with O 2 is found to be very slow; our data suggest that the rate coefficient for this reaction at 240 K is less than 5.0 × 10 −18 cm 3 molecule −1 s −1. Rate coefficients for CS 2 Cl reactions with CS 2 Cl ( k 3), NO ( k 5), and NO 2 ( k 6) were measured at 240 K and, in units of 10 −11 cm 3 molecule −1 s −1, were found to be 2 k 3 = 15 ± 6, k 5 = 2.2 ± 0.5, and k 6 = 1.3 ± 0.4, where the uncertainties are estimates of accuracy at the 95% confidence level.