Photodissociation dynamics of acetoxime in gas phase

The dynamics of photodissociation of acetoxime at 193nm, leading to the formation of (CH3)2CN and OH fragments, has been investigated. The nascent OH radicals, which are both rotationally and vibrationally excited, were probed by laser photolysis–laser induced fluorescence technique. OH fragments in both v″=1 and v″=0 vibrational states were detected with a ratio of population in the higher to lower level of 0.07±0.01. The rotational temperatures of v″=0 and 1 levels of OH radicals are 2650±150K and 1290±20K, respectively. More than 30% of the available energy, i.e., 115±21kJmol−1 is partitioned into the relative translational energy of the fragments. The results of excited electronic state and transition state calculations at the configuration interaction with single electronic excitation level suggest that the dissociation takes place with an exit barrier of ∼126kJmol−1 at the triplet state (T2) potential energy surface, formed by internal conversions/intersystem crossing from the initially populated S...