The formation of nitriles in hydrocarbon-rich atmospheres of planets and their satellites: laboratory investigations by the crossed molecular beam technique.

Crossed molecular beam experiments of cyano radicals, CN(X(2)Sigma(+)), reacting with unsaturated hydrocarbons have been performed to investigate synthetic routes to nitriles formation in hydrocarbon-rich atmospheres of planets and their moons. We have verified that all cyano radical reactions with acetylene, ethylene, methylacetylene, allene, benzene, and dimethylacetylene proceed without entrance barrier, have exit barriers well below the energy of the reactant molecules, and are strongly exothermic. The identification of the CN versus H atom exchange channel makes these reactions compelling candidates to synthesize unsaturated nitriles in solar system environments. Some of these nitriles, hitherto unobserved in our solar system, now represent an ideal target to be detected in the future Cassini-Huygens mission to Titan.