Photofragment translational spectroscopy of p-bromotoluene at 266 nm

Photodissociation of p-bromotoluene at 266 nm has been investigated on the universal crossed molecular beam machine, and translational energy distribution P(Et) as well as the anisotropy parameter β have been obtained. Photofragment translational energy distribution P(Et) reveals that ∼38.5% of the available energy is partitioned into translational energy. The anisotropy parameter β is determined to be −0.4±0.2. From P(Et) and β, we deduce that p-bromotoluene photodissociation is a fast process and the perpendicular transition plays a central role at this wavelength. The possible mechanism has been discussed and comparison of p-bromotoluene with bromobenzene, o-bromotoluene has also been made.