Identiˉcation and Chemistry of Phenylnitrene in Premixed Pyridine/Oxygen/Argon Flame with Tunable Synchrotron Photoionization

The triplet state phenylnitrene (PhN) species generated from the low-pressure (4.0 kPa) premixed laminar pyridine/oxygen/argon °ame was detected and identiˉed using tunable synchrotron vacuum ultraviolet photoionization and molecular-beam mass spectrometry techniques. The ionization energies of PhN were determined experimentally by photoionization e±ciency spectra and theoretically by calculations. The results indicate that PhN has a 3A2 ground state and its ˉrst and second adiabatic ionization energies are 8.04 and9.15§0.05 eV, respectively. Furthermore, the formation and consumption pathways of PhN are proposed according to the species detected in the present work. PhN is the ˉrst nitrogen-containing diradical detected in combustion chemistry, and so it should be added to the kinetic model of pyridine °ames.