Studies in vacuum ultra-violet photolysis Part V: The photolysis of cyclobutanone at 147.0 nm and 123.6 nm in the gas phase

The vacuum ultra-violet photolysis of cyclobutanone in the gas phase has been carried out at 147.0 and 123.6 nm. Two primary photochemical processes which produce vibrationally excited products have been shown to be important at these wavelengths: {A figure is presented} Radical processes are unimportant, the main reaction products arising either from the primary molecular reactions or subsequent isomerization or decomposition of vibrationally excited molecules. The ratio of the quantum yields of reactions (1) and (2) is a function of the wavelength of the exciting light and has a high pressure limiting value of 0.95 ± 0.05 and 0.45 ± 0.05 at 147.0 and 123.6 nm respectively. Detailed RRKM calculations have indicated that the cyclopropane molecule has, on average, 17 and 30 kJ/mol excess vibrational energy from the photochemical reactions at 147.0 and 123.6 nm respectively. Fluorescence of electronically excited CO has not been observed and the implications of this fact are discussed. © 1974.