Reactions of electronically excited molecular nitrogen with H₂ and H₂O molecules: theoretical study

Comprehensive quantum chemical analysis with the usage of the second-order perturbation multireference XMCQDPT2 approach was carried out to study the processes in the  +  H₂ and  +  H₂O systems. The energetically favorable reaction pathways have been revealed based on the exploration of potential energy surfaces. It has been shown that the reactions  +  H₂ and  +  H₂O occur with small activation barriers and, primarily, lead to the formation of N₂H  +  H and N₂H  +  OH products, respectively. Further, the interaction of these species could give rise to the ground state and H₂ (or H₂O) products, however, the estimations, based on RRKM theory and dynamic reaction coordinate calculations, exhibited that the  +  H₂ and  +  H₂O reactions lead to the dissociative quenching predominately. Appropriate rate constants for revealed reaction channels have been estimated by using a canonical variational theory and capture approximation. Corresponding three-parameter Arrhenius expressions for the temperature range T  =  300  −  3000 K were reported. (paper)