Energy partitioning in the quenching reaction N2(A 3Σ+u, v i)+N(4S) →N(2P or 2D) +N2(X 1Σ+g, v f) in solid nitrogen

The vibrational excitation of N2 observed in the quenching of triplet N2 by a nitrogen atom in a solid matrix is explained by a short-range interaction N2(3Σ+uvi ?0)+N(4S) →N(2D, 2P)+N2(1Σ+gvf ≫0). The golden-rule model gives a simple interpretation of the vibrational distribution vf as a shifted Franck–Condon envelope 〈vi‖vf〉. We treat this system by calculating classical trajectories on an empirical but entirely a priori potential surface of the appropriate N3 states. For that purpose the LEPS formalism for three σ electrons is extended to nine electrons belonging to σ as well as π orbitals. Using a simple surface-hopping method we compare different nonadiabatic pathways. An atom exchange described by a unique diabatic potential seems to be the dominant reaction channel. Agreement between Monte Carlo averaged calculation of the vibrational distribution vf and experiment is surprisingly good considering that no parameter is fitted.