Single rotational product propensity in the photodissociation of HOD.

Photodissociation of HOD from the B state has been studied using the high resolution rydberg "tagging" time-of-flight (TOF) technique. The TOF spectra show an unusually strong population (approximately 50%) for a single rotational state for the OD (A(2)Sigma, upsilon = 0) fragments. Through theoretical studies, this phenomenon, which we have labeled the "single rotational product propensity," is attributed to a dynamically constrained threshold effect in the photodissociation of the HOD molecule on the B state.