THE STUDY OF VIBRATIONALLY EXCITED N2 MOLECULES WITH THE AID OF AN ISOTHERMAL CALORIMETER

Abstract

Vibrationally excited nitrogen molecules produced both by a microwave discharge in nitrogen and also by the reaction[Formula: see text]have been examined using an isothermal calorimetric probe.In the first case the energy associated with an 'active' nitrogen stream, due to vibrationally excited N2, was found to be 6.03 kcal mole−1 of total nitrogen. The subsequent relaxation of this species was found to occur almost entirely on the walls of the reaction vessel, with a collision efficiency of 4.5 × 10−4. The addition of other gases greatly accelerated the homogeneous relaxation rate. Collisional efficiencies of N2O, CO2, and Ar were found to be 0.8 × l0−4, 2.3 × 10−5, and 1.0 × 10−6 respectively.The vibrationally excited nitrogen produced by the N/NO reaction was found to possess 20 ± 4 kcal mole−1 of energy compared with the maximum of 75 kcal mole−1 allowed by the exothermicity of the reaction.