RATE CONSTANTS FOR THE REACTIONS OF N-2(+) WITH O-2 AS A FUNCTION OF TEMPERATURE (300-1800 K)( AND N)

We have measured the rate constants for the reactions of N+ and N-2(+) with O-2 from room temperature to 1600 and 1800 K, respectively. In t he N+ reaction the rate constants increase with increasing temperature to 1000 K and level out at the collisional value above that. For the N-2(+) reactions the rate constant decreases with temperature to 1000 K and increases above that value. Internal temperature dependences are derived by combining the data with previous drift tube measurements. The internal energy dependence of the N+ reaction appears to be a comp licated function of vibrational, rotational, and electronic energy. In the N-+(2) reaction, rotational and translational energy behave simil arly, and O-2 vibrations are found to increase the rate constant drama tically. If all O-2 vibrations are involved, a factor of six enhanceme nt is found. Alternatively, O-2 (nu = 2) allows exothermic production of O-2 + (a(4) Pi(u)). If the enhancement is due to this channel, then a factor of 20 enhancement is derived. (C) 1997 Elsevier Science B.V.