Infrared multiphoton dissociation of the BCl3.CH3SH complex

A mixture of BCl3 and CH3SH in the gas phase was found to have an infrared absorption with three peaks at around 1000 cm-1. The absorption was tentatively assigned to the BCl3.CH3SH complex. The infrared multiphoton dissociation of the complex has been examined by using a CO2 TEA laser. The threshold laser fluence required for the dissociation was about 0.5 J cm-2, being smaller than that for BCl3 itself by an order of 2. The dissociation rate of 10BCL3.CH3SH was 10 times larger than that of 11BCl3.CH3SH for the laser irradiation at 944 cm-1. The dependence of the specific dissociation rate on the absorbed energy suggests that two reaction paths with different activation energies exist; the paths are the Cl atomic and HCl molecular elimination from vibrationally excited complex molecules