Ultraviolet photodissociation dynamics of the n-propyl and i-propyl radicals.

Ultraviolet (UV) photodissociation dynamics of jet-cooled n-propyl (n-C3H7) radical via the 3s Rydberg state and i-propyl (i-C3H7) radical via the 3p Rydberg states are studied in the photolysis wavelength region of 230–260 nm using high-n Rydberg atom time-of-flight and resonance enhanced multiphoton ionization techniques. The H-atom photofragment yield spectra of the n-propyl and i-propyl radicals are broad and in good agreement with the UV absorption spectra. The H + propene product translational energy distributions, P(ET)’s, of both n-propyl and i-propyl are bimodal, with a slow component peaking around 5-6 kcal/mol and a fast one peaking at ∼50 kcal/mol (n-propyl) and ∼45 kcal/mol (i-propyl). The fraction of the average translational energy in the total excess energy, 〈fT〉, is 0.3 for n-propyl and 0.2 for i-propyl, respectively. The H-atom product angular distributions of the slow components of n-propyl and i-propyl are isotropic, while that of the fast component of n-propyl is anisotropic (with an ...