The velocity dependence of the excitation transfer reaction Ar(3P2,0) + N2(X 1Σ+g) → Ar(1S) + N2(C 3Πu)

Publisher Website
Google Scholar
Abstract
The velocity dependence of the title reaction was determined using crossed effusive molecular beams with one beam time‐of‐flight velocity selected. The basis of the method is discussed, and the resolution is derived in terms of the experimental parameters. The velocity dependence was determined over the range 390–1630 m/s, corresponding to 0.013–0.226 eV relative energy. The cross section rises rapidly to 0.10 eV above which it is nearly constant to 0.226 eV. The thermal rate constant temperature dependence is calculated from the cross section energy dependence and normalized to the literature value for the rate constant at 300 °K. The cross section function over the energy range studied accounts for ≳ 90% of the rate constant over the temperature range 78–600 °K. The activation energy is calculated over the range 50–700 °K from the cross section function and compared with the threshold energy E0. Comparison of the present work with previous studies of the total quenching of Ar(3P2,0) by N2 indicates that the cross sections for formation of N2(B 3Πg) and N2(C 3Πu) have a similar energy dependence below 0.05 eV. If these two states are formed via a common complex as previously proposed, this similarity suggests that the dependence on energy is primarily that for complex formation rather than for the subsequent partitioning into N2(B) and N2(C) +Ar(1S) products.