A Theoretical Investigation of the Reaction N(2D) + C6H6 and Implications for the Upper Atmosphere of Titan

The reaction between nitrogen atoms in their first electronically excited state 2D with benzene has been characterized by electronic structure calculations of the stationary points along the minimum energy path. According to this study, there are six open channels leading to C6H5N (phenylnitrene) + H, C6H4 + NH2, C5H5 (cyclopentadienyl) + HNC, C5H5CN + H, C5H4 + HCNH and C5H5N (pyridine) + CH. There is no barrier in the entrance channel, so that the N(2D) + C6H6 reaction is expected to be very fast also under the low temperature conditions of Titan, the massive moon of Saturn. The possible impact of the title reaction in the chemistry of the upper atmosphere of Titan, where benzene is present and atomic nitrogen in 2D state can be efficiently produced by a series of high-energy processes, is also discussed.