Electronic-excitation transfer collisions in flames—VI. Interpretation of the temperature dependence of alkali-quenching by N2 and general conclusions about the energy transfer mechanism

The experimental temperature dependence of alkali-N₂ quenching cross sections is explained semi-quantitatively by a simple theoretical model, based on an ionic intermediate state, in which attractive van-der-Waals forces play an essential role. Using this model, quenching experiments are compared with Na(3²P)-N₂ excitation measurements in molecular beams. From this comparison it is concluded that the distribution of relative cross sections for specific vibrational transitions during the quenching process can be described by a distribution calculated by Fisher,⁽⁸⁾ whereas the distribution given by Bjerre⁽¹⁸⁾ has to be rejected. Resonant vibrational-electronic energy transfer is not important.