The 355 nm laser photolysis of jet-cooled methyl nitrite (CH₃ONO). Internal energy distributions of the NO fragment

The photodissociation of methyl nitrite (CH₃ONO) at 355 nm in a supersonic free-jet expansion has been studied by state-resolved two-proton laser-induced fluorescence of the NO fragment. The vibrational population distribution of the nascent NO is much colder than reported for the photodissociation of 300 K vapour and can be understood on the basis of the direct electronic dissociation of a very short-lived excited complex. The conformational isomerism of CH₃ONO and the assignment of the structure of its electronic absorption spectrum prove to be important for the interpretation of the observed dissociation dynamics in the jet and at 300 K. © 1992.