The dynamics of OH channel in the 266 and 355 nm photodissociation of 2-nitrophenol

Photodissociation of gaseous 2-nitrophenol at 266 and 355 nm was investigated by probing the nascent OH products with the laser-induced-fluorescence (LIF) technique. Rotational state distributions of the OH photofragments were measured and characterized by Boltzmann temperatures of 900 ± 40 K and 1070 ± 80 K at 266 and 355 nm, respectively. The OH photoproducts were found to be vibrationally cold at both photolysis wavelengths. Preferential populations of the OH F1 (Π3/2) spin–orbit state and Π+ Λ-doublet state were observed at both photolysis wavelengths. We have proposed a mechanism for OH production involving the photoisomerization to form aci-nitro isomers, which then dissociate into OH fragments.