Measurements of Temperatures of Vibrationally Excited N2

A comparison of the vibrational and rotational temperatures of microwave discharged N₂ as measured by the CO tracer and the Penning ionization with He(2³S) techniques has been performed in a flow tube apparatus. A vibrational temperature range of 1000–3000°K was covered at a kinetic temperature of ∼350°K. A detailed analysis of each technique is presented. The effect of pressure quenching of the ${\mathrm{N}}_2^{+}\text{(1−)}$ radiation occurring in the Penning ionization technique and the effect of vibrational temperature gradient across the flow tube in the CO tracer technique are discussed. Because of the good agreement of vibrational temperatures deduced from the two techniques, it is concluded that the Treanor‐Teare relationship between the vibrational temperatures of diatomic gases in binary mixture in the $\mathrm{V–V}$ quasiequilibrium regime is valid. This work represents the first experimental confirmation of this relationship. The agreement of rotational temperatures implied by the ${\mathrm{N}}_2^{+}$ and CO spectra indicates that the rotational distribution in ${\mathrm{BN}}_2^{+}\mathrm{(v\prime )}$ is not significantly distorted from the N₂ equilibrium distribution by the heavy He(2³S) impact.