Vacuum ultraviolet photodissociation dynamics of methanol at 121.6 nm

Abstract Vacuum ultraviolet (VUV) photodissociation of CH 3 OH and CH 3 OD at 121.6 nm was studied using high- n Rydberg atom time-of-flight (HRTOF) technique. The H-atom product TOF spectrum of CH 3 OH and D-atom spectrum of CH 3 OD have bimodal distributions. O–H (CH 3 O + H(D)) and C–H (CH 2 OH(D) + H) dissociations contribute to the fast component. The slow component corresponds to CH 2 O + H + H(D) production, mainly from three-body photodissociation, plus small contributions from secondary dissociation of CH 3 O and CH 2 OH(D). The CH 2 O + H + H formation is the major photodissociation pathway, with a branching ratio of (CH 2 O + H + H):(CH 3 O + H):(CH 2 OH + H) ≈ 1:0.25:0.15.