O2(b1Σg+) Removal by H2, CO, N2O, CH4, and C2H4 in the 300-800 K Temperature Range.

Abstract

Rate constants for the removal of O2 b1Σg+ by collisions with species relevant to combustion, H2, CO, N2O, CH4 and C2H4 have been measured in the temperature range 297-800 K. O2(b1Σg+) was produced from ground-state molecular oxygen by photoexcitation 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 H2, CO, N2O, CH4, and C2H4 could be represented by the modified Arrhenius expressions kH2 = (1.44 ± 0.02) × 10-16 T1.5 exp[(0 ± 10)/ T], kCO = (6.9 ± 0.4) × 10-24 T3 exp[(939 ± 33)/ T], kN2O = (2.63 ± 0.14) × 10-18 T1.5 exp[(590 ± 26)/ T], kCH4 = (3.5 ± 0.2) × 10-17 T1.5 exp[(-220 ± 24)/ T], and kC2H4 = (2.34 ± 0.10) × 10-20 T2.5 exp[(680 ± 16)/ T] cm3 molecule-1 s-1, respectively. All of the rate constants measured at room temperature were found to be in good agreement with previously reported values, whereas the values at elevated temperatures up to 800 K were systematically measured for the first time.