Collisional electronic quenching of NO A 2Σ+ by N2 from 300 to 4500 K

We report rate coefficients for electronic quenching of NO A 2Σ+ v′=0 by N2 measured at room temperature and at high temperatures behind reproducible shock waves. The quenching cross section increases from 0.007 Å2 at 300 K to 7 Å2 at 4500 K, and the temperature dependence in the range 300–2300 K is best understood using a charge-transfer (harpoon) collision model. We also record dispersed fluorescence spectra and time-resolved fluorescence from both the directly pumped level (v′=0) and a collisionally populated level (v′=1); from these results we obtain rate coefficients for vibrational energy transfer in NO (A) and electronic quenching of v′=1 at 1900 K.