Chemistry of Nitrogen Compounds in Combustion Processes

摘要

The major tasks under the current contract have in general involved the photochemistry and kinetics of nitrogenous molecules, using F2 and KrF excimer lasers as initiating sources. The results of this three-year program are summarized below. NO2 has been dissociated at 2485, revealing in its nascent NO vibrational distribution a very strong inversion, in which vibrational levels near the thermodynamic limit of v = 8 are strongly populated. Resonance excitation of NO by the 1576 F2 laser line has been observed and the spectroscopy clarified. The O2(A superscript 3 sigma u(+)) state by laser-induced fluorescence (LIF) has been studied. Radiative lifetimes of the CN(A superscript 2 pi) state have been measured for v = 0-5. Quenching rate coefficients of CN(A superscript 2 pi) by C2N2 have been determined for v = 0-5. An evaluation of the heat of formation of NCO indicates that the most recent determination is inconsistent with kinetic requirements and must be re-interpreted. Photodissociation of C2N2 at 1576 populates CN(A superscript 2 pi) up to the one-photon limit of v = 5, with a strong maximum occuring at v = 2. Simultaneous photodissociation of C2N2 and O2 at 1576 results in greatly enhanced CN(A) and CN(B) emission intensities over those obtained in the absence of O2, due to slow secondary processes.