Theoretical study of reactions relevant for atmospheric models of Titan

Chemical reactions involving atomic nitrogen are of relevance in a variety of natural environments, such as the upper terrestrial atmosphere and the atmospheres of other planets, in particular Titan, the largest moon of Saturn, which is the only solar system body to have a dense atmosphere mainly composed of molecular nitrogen like the Earth. The dynamics of the H-displacement channels in the reactions N(2D) + CH4, C2H6 and C2H4 have been investigated by the crossed molecular beam technique with mass spectrometric detection and time-of-flight analysis at different collision energies. The interpretation of the scattering results is assisted by ab initio electronic structure calculations of stationary points and product energetics for the CH4N, C2H6N and C2H4N ground state doublet potential energy surfaces (PES). The PES were investigated by localizing the lowest stationary points at the B3LYP level of theory in conjuction with the correlation consistent valence polarized aug-cc-pVTZ basis set. The energies of all the stationary points were refined by performing CCSD(T) calculations using the same aug-cc-pVTZ basis set.