Production of Vibrationally Excited Species from the Photolysis of Nitroso Compounds

Abstract

THERE have been a number of recent investigations on the production of Vibrationally excited species by the method of flash photolysis^1–5 with particular reference to two possible mechanisms, direct vibrational excitation or the initial formation of an electronically excited state the energy of which is then reorganized internally. Basco and Norrish¹ have concluded that vibrationally excited nitric oxide was produced directly on photolysing nitrosyl chloride, whereas Symons and Yarwood^4,5 have interpreted their observation of the production of CCl radicals in the photolysis of a number of halogenated methanes in terms of the formation of an electronically excited substituted methyl radical the energy of which was internally converted into vibration. Experiments have been carried out on the flash photolysis of trichloronitrosomethane (CCl₃NO) in an attempt to determine the fraction of energy appearing as vibration in each fragment produced on photolysis and to attempt to determine which of the two possible mechanisms is operative in this case. A new transient spectrum resulting from the photolysis of this molecule is also reported.