Photodissociation of i-C3H7I within the A band and anisotropy-based decomposition of the translational energy distributions

The photodissociation of i-propyl iodide in the A absorption band was studied by using velocity map ion imaging following excitation between 304 and 253 nm. The translational energy distributions and translational energy dependence of the angular distributions of the I P-2(3/2) and P-2(1/2) photofragments were recorded as a function of the photodissociation wavelength. These distributions are used to decompose the i-C3H7+I P-2(3/2) channel into contributions from two processes: Excitation to the (3)Q(0)(+) state followed by crossing onto the (1)Q(1) surface, and direct excitation to the (3)Q(1) surface followed by dissociation on that surface. As in the case of methyl iodide, the former process dominates; the latter process contributes only in the red wing of the absorption band, with its contribution peaking at similar to 287 nm with an absorption of similar to 1% of the band maximum. The data for the i-C3H7+I-* P-2(1/2) channel display a smooth behavior across the full energy range of the present study, and are consistent with direct excitation to the (3)Q(0)(+) surface followed by dissociation on that surface.