Absolute rate coefficient of the reaction of CF2(ã 3B1) with O2 between 288 and 600 K
Abstract
The rate coefficient of the removal of electronically excited CF2(ã 3B1) by O2 (quenching as well as reaction) has been determined for the first time over an extended temperature range (288–600 K). CF2(3B1) radicals were generated by pulsed laser photolysis of C2F4 at 193 nm and real-time pseudo-first-order decays of the relative CF2(3B1) concentration were obtained by monitoring the CF2(3B1 → 1A1) emission at 570–700 nm. This new CF2(3B1)-generation technique allows a straightforward determination of the absolute rate constants. Over the experimental temperature range, the rate coefficient exhibits a simple Arrhenius behaviour with a small activation energy, described by: koxygen(T) = (6.7 ± 1.9) × 10−12 exp[−(200 ± 100)K/T] cm3 s−1 molecule−1. No pressure dependence was observed over the 1–20 Torr range using He as the bath gas.