COLLISIONAL DEACTIVATION OF O-2(1-SIGMA-G+) BY SMALL POLYATOMIC-MOLECULES

Literature data on the collisional deactivation Of O2(1-SIGMA(g)+) by small polyatomic molecules in the gas phase are interpreted by a deactivation model which has proven to describe successfully the experimental findings for the collisional deactivation of O2(1-SIGMA(g)) in the liquid phase. Deactivation occurs by electronic to vibrational energy transfer from the excited 02 molecule to peripheral bonds X - Y of the quenching molecule. Using data on Franck-Condon factors and transition energies for the possible coupled transitions O2(1-SIGMA(g)+, nu = 0 --> 1-SIGMA(g), nu = m) and X - Y (nu' = 0 --> nu' = n) experimental rate constants k(XY)SIGMA of O2(1-SIGMA(g)+) quenching by X - Y can quite well be reproduced by calculated ones. The only parameter of the model which has to be changed is related with the electronic factor f of the corresponding O2 transition. As ratio of electronic factors of the 1-SIGMA(g) --> 3-SIGMA(g)- singlet-triplet and 1-SIGMA(g)+ --> 1-SIGMA(g) singlet-singlet transitions f(ST)/f(SS) = 6 . 10(-5) is obtained. Independent measurements of radiative lifetimes of these transitions in an Ar-matrix yield f(ST)/f(SS) = 9 . 10(-5) confirming our results. Thus for the first time collisional deactivation of O2(1-SIGMA(g)) and O2(1-SIGMA(g)+) by small polyatomic molecules is explained consistently.