THERMAL RATE CONSTANTS OF THE N-2-]NO+N REACTION USING AB-INITIO (3)A'' AND (3)A' POTENTIAL-ENERGY SURFACES(O)

Theoretical determinations of the thermal rate constants and product e nergy distributions of the N-2+O-->NO+N reaction, which plays a crucia l role in hydrocarbon air combustion and high temperature air chemistr y, are carried out using a quasiclassical trajectory method. An analyt ical fit of the lowest (3)A' potential energy surface of this reaction based on the CCI ab initio data is obtained. The trajectory study is done on this surface and an analytical 3A '' surface proposed by Gilib ert et al. [J. Chem. Phys. 97, 5542 (1992)]. The thermal rate constant s computed from 3000 to 20 000 K are in good agreement with the availa ble experimental data. In addition, the dependence of the rate constan t on the N-2 internal state is studied. It is found that a low vibrati onal excitation can reduce the rate constant of this reaction by a fac tor of 3. Also, we investigate the effect of the N-2 vibrational state on the product NO vibrational distribution, and it is found that at l ow Nz vibrational states, the NO vibrational distribution is nearly Bo ltzmann. However, at N-2(v>10), the product distribution is almost uni form at low energy levels. (C) 1996 American Institute of Physics.