Reaction dynamics of Cl+CH₃SH: Rotational and vibrational distributions of HCl probed with time-resolved Fourier-transform spectroscopy

Rotationally resolved infrared emission of HCl was detected with a step-scan Fourier-transform spectrometer in a laser-initiated reaction of Cl+CH₃SH. The average rotational energy and its fraction of partition derived, E_r=8.2±0.9 kJ mol^-1 and _r=0.10±0.01, were much greater than the previous results. The difference in vibrational excitation was consistent with a difference in predicted H-Cl bond distances in transition structures of these reactions. The time-resolved Fourier-transform spectra demonstrated improved temporal resolution and detection sensitivity in determining internal-state distributions of products from bimolecular reactions.