Photodissociation dynamics of ICN. Unequal population of the CN X2Σ+ fine-structure components
Abstract
Photolysis of ICN at 281.5, 266 and 249 nm produces CN X2Σ+ fragments in which the population of the F1(J″=N″+½) and F2(J″=N″–½) fine-structure components vary markedly as a function of v″, N″ and dissociation wavelength. Population differences favour either F1 or F2, and can be > 2:1. A model is proposed to explain this behaviour, in which out-of-plane, spin-dependent forces cause the electron spin on CN to have a preferred orientation with respect to rotation of the CN fragment. The strong N″ dependence of the F1/F2 ratio is attributed to interference between different dissociation channels, probably enhanced by various curve crossings.