O 2(b 1 Σ g+) Quenching by O 2, CO 2, H 2 O, and N 2 at Temperatures of 300-800 K

J Phys Chem A. 2017 Oct 5;121(39):7343-7348. doi: 10.1021/acs.jpca.7b07885. Epub 2017 Sep 26.

Abstract

Rate constants for the removal of O2(b1Σg+) by collisions with O2, N2, CO2, and H2O have been determined over the temperature range from 297 to 800 K. O2(b1Σg+) was excited by pulses from a tunable dye laser, and the deactivation kinetics were followed by observing the temporal behavior of the b1Σg+-X3Σg- fluorescence. The removal rate constants for CO2, N2, and H2O were not strongly dependent on temperature and could be represented by the expressions kCO2 = (1.18 ± 0.05) × 10-17 × T1.5 × exp[Formula: see text], kN2 = (8 ± 0.3) × 10-20 × T1.5 × exp[Formula: see text], and kH2O = (1.27 ± 0.08) × 10-16 × T1.5 × exp[Formula: see text] cm3 molecule-1 s-1. Rate constants for O2(b1Σg+) removal by O2(X), being orders of magnitude lower, demonstrated a sharp increase with temperature, represented by the fitted expression kO2 = (7.4 ± 0.8) × 10-17 × T0.5 × exp[Formula: see text] cm3 molecule-1 s-1. All of the rate constants measured at room temperature were found to be in good agreement with previously reported values.