ULTRA-LOW-TEMPERATURE REACTIONS OF CARBON ATOMS WITH HYDROGEN MOLECULES

The reactions of carbon atoms with dihydrogen have been investigated in liquid helium droplets at T = 0.37 K. A calorimetric technique was applied to monitor the energy released in the reaction. The barrierless reaction between a single carbon atom and a single dihydrogen molecule was detected. Reactions between dihydrogen clusters and carbon atoms have been studied by high-resolution mass spectrometry. The formation of hydrocarbon cations of the type CmHn+ with m = 1-4 and n = 1-15 was observed. With enhanced concentration of dihydrogen, the mass spectra demonstrated the main magic peak assigned to the CH5+ cation. A simple formation pathway and the high stability of this cation suggest its high abundance in the interstellar medium.