Photodissociation dynamics of the methyl radical 3s Rydberg state

The photodissociation dynamics of methyl radical have been investigated at 193.3 nm using photofragment translational spectroscopy. The formation of CH₂ and H(²S) was the only dissociation pathway observed. Although it is not possible to assign the spin state of the methylene unambiguously, we believe that methylene is produced predominately in the ã ¹A₁ excited state. The translational energy distribution of the products is peaked at ∼13 kcal/mole which is consistent with the magnitude of the exit barrier on the excited state potential energy surface. The breadth of the distribution suggests that the methyl radicals dissociate from a wide range of geometries. From the photofragment angular distribution an anisotropy parameter of β=-0.9±0.1 was determined.