Laser spectroscopy of the CN radical and astrophysical applications

The formation of CN radicals by flash photolysis of a number of parent molecules was monitored by laser induced fluorescence in the B2Sigma(plus)-X2Sigma(plus) transition of CN. The rotational and vibrational energy of the newly formed radicals in the X state was measured directly. Formation of CN(A2Pi) in the lower vibrational levels was determined by an indirect method based on resonant energy transfer to higher vibrational levels of the ground state. These laboratory studies have shown that high initial internal excitation of CN with rotational levels of maximum N equals 50-70 is the rule. In general, the formation of simple molecules in excited states is commonly the case. There appear to be astrophysical systems where radiation from these excited levels may be detectable. Such observations would serve as a probe of molecular formation.