Detection of the perpendicular A state transitions of CH3I by imaging of photofragment angle-velocity distributions.

Photofragment angle-velocity distributions are measured in a molecular beam using a new two-dimensional imaging technique. We report on the detection of weak perpendicular transitions for CH3I A state photodissociation at 266 and 304 nm. The ratio of cross sections and the 3Q0-1Q crossing probability are σ⊥/σ||=0.00-0.10 and p=0.22-0.27 at 266 nm and σ⊥/σ||=0.20-0.30 and p=0.43-0.48 at 304 nm. [ABSTRACT FROM AUTHOR]