COMPARATIVE-ANALYSIS OF THE COLLISIONAL DEACTIVATION OF O2(1-DELTA-G), O2(1-SIGMA-G+), SO(1-SIGMA+), SEO(1-SIGMA+) AND NF(1-SIGMA+) BY SMALL POLYATOMIC-MOLECULES

Literature data on the collisional deactivation of the 1DELTA(g) and 1SIGMA(g)+ states of O2 and the 1SIGMA+ states of SO, SeO and NF are analysed comparatively. Deactivation of the excited diatomic molecule AB from the upper (AB(u)) to the lower (AB(l)) electronic state takes place with a rate constant k(XY) by electronic to vibrational energy transfer to a single terminal bond X-Y of the quenching molecule. Quenching is considered to occur in coupled transitions AB(u)(upsilon = 0) --> AB(l)(upsilon = m) and X-Y(upsilon' = 0 --> upsilon' = n). The variation of k(XY) over 11 orders of magnitude is reproduced using Franck-Condon factors and energies of the respective transitions. The quantitative evaluation demonstrates that the electronic factors of the AB(u) --> AB(l) transitions in the deactivation of the 1SIGMA+ states of O2, SO, SeO and NF are near unity. This result is in accordance with the observation that the spin-allowed 1SIGMA+ --> 1DELTA transition is involved in 1SIGMA+ activation and indicates that symmetry and orbital restrictions disappear in collisional deactivation. The electronic factor of the spin-forbidden 1DELTA(g) --> 3SIGMA(g)- quenching of O2 is about 6X10(-5) times smaller than that of the spin-allowed 1SIGMA(g)+ --> 1DELTA(g) deactivation.