ArF laser photodissociation dynamics of hydroxyacetone: LIF observation of OH and its reaction rate with the parent

Abstract

Upon photoexcitation at 193 nm, hydroxyacetone dissociation appears to give CH₃ and COCH₂OH radicals as primary products, and the latter undergoes further dissociation to OH and ketene. Real time LIF observation of OH formation shows a dissociation rate of COCH₂OH as (4.6± 0.5)× 10⁶ s^-1. There is no significant population (<1%) in excited vibrational levels of OH (X²π ) observed. The rotational state distribution has a Boltzmann temperature of the OH photofragment 380± 40 K. Doppler spectroscopy shows an average translational energy with the OH photofragment as 3.6± 1.3 kcal mol^-1. The bimolecular rate constant for OH + hydroxyacetone is (2.8± 0.2) × 10^-12 cm³ molecule^-1 s^-1.