Imaging H abstraction dynamics in crossed molecular beams: O(3P) + propanol isomers

Abstract

The crossed beam reaction dynamics of ground state O(³P) atoms with propanol isomers (1-propanol and 2-propanol) have been studied for the first time using the velocity map imaging technique. The hydroxypropyl radical products, generated from H-abstraction of the secondary and tertiary C–H groups of propanol isomers, were detected via single photon ionization at 157 nm under single collision conditions with collision energies of 8 and 10 kcal mol⁻¹. Direct rebound dynamics were suggested by the angular distributions, which show overall sideways-backward scattering but more pronounced backward scattering for both isomer reactions under all collision energies studied here. All the translational energy distributions peak at low energy, on average 20–40% of the total available energy. This indicates high internal excitation in the products that is treated by various models of energy release. We infer that most of the total available energy is partitioned into rotational excitation due to the long-rang dipole–dipole interaction between the dipolar OH and hydroxypropyl radicals.