Ultraviolet Photodissociation Dynamics of 1-Propanol and 2-Propanol by High-n Rydberg-Atom Time-of-flight(HRTOF) Technique

193.3 nm photodissociation dynamics of jet-cooled 1-propanol and 2-propanol has been examined by using high-n Rydberg-atom time-of-flight (HRTOF) technique. Isotope labeling study indicates that O-H bond fission is the primary H-atom production channel. Center-of-mass (CM) product translational energy release of this channel is large, with 〈fT〉= 0.76 for H+1-propoxy and 0.78 for H+2-propoxy. Maximum CM translational energy release yields an upper limit of the O-H bond dissociation energy: (432±2)kJ/mol in 1-propanol and (433±2)kJ/mol in 2-propanol. H-atom product angular distribution is anisotropic (with β≈-0.79 for 1-propanol and -0.77 for 2-propanol), indicating a short excited-state lifetime. The 193.3 nm H-atom dissociation of both 1-propanol and 2-propanol is prompt and occurs on a repulsive excited-state potential energy surface.