D atom loss in the photodissociation of the DNCN radical: Implications for prompt NO formation

The photodissociation of DNCN following excitation of the CA″2←XA″2 electronic transition was studied using fast beam photofragment translational spectroscopy. Analysis of the time-of-flight distributions reveals a photodissociation channel leading to D+NCN competitive with the previously observed CD+N2 product channel. The translational energy distributions describing the D+NCN channel are peaked at low energy, consistent with internal conversion to the ground state followed by statistical decay and the absence of an exit barrier. The results suggest a relatively facile pathway for the reaction CH+N2→H+NCN that proceeds through the HNCN intermediate and support a recently proposed mechanism for prompt NO production in flames.