The photodissociation dynamics of the jet-cooled thiomethoxy radical (CH3S) via the B2A2 &lt;--X2E transition is studied in the UV region of 216 – 225 nm by using high-n Rydberg H-atom time-of-flight (HRTOF) technique. The H-atom product channel is observed directly from the H-atom time-of-flight (TOF) spectra (from both dimethyl disulfide and dimethyl sulfide precursors). The H-atom photofragment yield (PFY) spectrum shows two peaks at 220.3 and 221.5 nm and are assigned to the B2A2 &lt;--X2E3/2 and B2A2 &lt;--X2E1/2 transitions, respectively. Several dissociation channels are observed. The excited state CH3S has a repulsive dissociation to the H + CH2S(X2A1) products with an anisotropic angular distribution and the CH2S product C-S stretch vibrational state resolved. A Franck-Condon modeling is performed to provide the geometry information of the C-S bond distance when the C-H bond breaks. The main dissociation channel is a statistical H + CH2S(X2A1) product channel via unimolecular dissociation of internally hot CH3S radical on the ground electronic state after internal conversion from the electronic excited state. The H + CH2S(A1A2) and H + CH2S(a3A2) product channels are also observed but are minor channels.

H-atom product channel in the ultraviolet photodissociation of the thiomethoxy radical (CH3S) via the B2A2 state

2019 Spring National Meeting

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