Cyanogen flash photolysis

McGrath and Morrow " studied the reactions of both 0( D) and 0( P) with cyanogen at room temperature by flash photolysis. The 0( D) was produced by the photolysis of ozone. The reaction was monitored by absorption spectroscopy. At first, they attributed the previously unidentified ultraviolet absorption bands at 3250-3330 A to the fulminate radical (CNO), concluding that the initial step of the reaction was... 

CN radicals appear to have been those of Paul and Dalby , who studied the kinetics of disappearance of CN formed from the flash photolysis of cyanogen under varying conditions. They determined the rate coefficient for the disappearance of CN in the presence of O2 to be 5.5 x 10 I.mole . sec , assuming there was no chain reaction occurring. The nature of the products of the reation was not determined. 

The photolysis of cyanogen azide has been examined in both the vapour and solid phases. In the solid phase, ESR measurements showed the presence of NCN using filtered radiation (2800-3000 A) and triplet CNN using unfiltered light. In the vapor phase flash photolysis, the following steps have been established by kinetic spectroscopy ... 

Primary photochemical processes also may yield vibrationally excited products. Flash photolysis of cyanogen, cyanogen bromide and cyanogen iodide in each case yields a product whose absorption spectrum identifies it as a vibrationally hot CN radical with up to 6 quanta of excitation. VibrationaUy excited nitric oxide in the ground electronic state (detected by the A absorption system) is... 

Studies of the photodissociation of cyanogen halides in the vacuum ultraviolet can be separated into two broad types (i) those which employed polychromatic flash photolysis and which were primarily concerned with the detection of electronic and/or vibrational laser action in the CN fragments, and (ii) those which employed continuous monochromatic photolysis sources and were primarily concerned with the branching ratios and energy disposal following dissociation from well-defined initially populated levels. 

Cyanogen Halides, Hydrogen Cyanide, and Cyanogen.—Studies of energy disposal in the near u.v. photodissociation of ICN have had a chequered career. In an early flash photolysis experiment it was concluded that CN was formed in its ground electronic state with little or no vibrational excitation. Subsequent theoretical treatments all agreed that this was a respectable conclusion but new... 

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