Dichromatic irradiation studies of \({{\text{C}}}_{2}\left({{\text{a}}}^{3}{\Pi }_{{\text{u}}}\right)\) radical formation with TEA CO₂ laser heating of C₂H₃Br/CF₂HCl mixtures

The process of Infrared Multiphoton Dissociation (IRMPD) was studied in a mixture of vinyl bromide/chlorodifluoromethane (VBr, C₂H₃Br/CF₂HCl) using single and double infrared pulsed transverse excitations atmospheric CO₂ laser beams. The dissociation of VBr was investigated using FTIR, and the product composition was analysed, and various dissociation routes were proposed. The study found that the VBr molecules were more heavily dissociated when exposed to the CF₂HCl environment than without it. By using a time-resolved LIF, the kinetics reactions with CF₂HCl were explored under pseudo-first-order conditions, and the quenching rate constant for the interaction between CF₂HCl and \({{\text{C}}}_{2}\left({{\text{d}}}^{3}{\Pi }_{{\text{g}}}\right)\) ${\text{C}}_2\left({\text{d}}^3,{\mathrm{\Pi }}_{\text{g}}\right)$ was published using the classical Stern–Volmer model. The impact of pulsed laser heating on the generation of \({{\text{C}}}_{2}\left({{\text{a}}}^{3}{\Pi }_{{\text{u}}}\right)\) ${\text{C}}_2\left({\text{a}}^3,{\mathrm{\Pi }}_{\text{u}}\right)$ radicals was also observed. The decrease in the intensity of the \({{\text{C}}}_{2}({{\text{a}}}^{3}{\Pi }_{{\text{u}}})\) ${\text{C}}_2({\text{a}}^3{\mathrm{\Pi }}_{\text{u}})$ LIF signal was due to faster recombination of the \({{\text{C}}}_{2}\left({{\text{a}}}^{3}{\Pi }_{{\text{u}}}\right)\) ${\text{C}}_2\left({\text{a}}^3,{\mathrm{\Pi }}_{\text{u}}\right)$ radicals, together with a decrease in \(V-V{\prime}\) $V-V\prime$ energy transfer and the pressure oscillations produced by the effect of pulsed laser heating in the irradiated volume and the experimental conditions.