Absolute Absorption Cross-Section of the Ã←X˜ Electronic Transition of the Ethyl Peroxy Radical and Rate Constant of Its Cross Reaction with HO2

The absolute absorption cross-section of the ethyl peroxy radical C2H5O2 in Ã←X˜ electronic transition with peak wavelength at 7596 cm−1 has been determined by method dual wavelengths time resolved continuous wave cavity ring down spectroscopy. radicals were generated from pulsed 351 nm photolysis C2H6/Cl2 mixture presence 100 Torr O2 T = 295 K. detected on one CRDS paths. Two methods have applied for determination cross-section: (i) based Cl-atoms being converted alternatively to either adding C2H6 or hydro radicals, HO2, CH3OH mixture, whereby HO2 was reliably quantified second path 2ν1 vibrational overtone 6638.2 (ii) reaction measured under excess concentration. Both lead same σ (1.0 ± 0.2) × 10−20 cm2. rate constant cross between and be (6.2 1.5) 10−12 cm3 molecule−1 s−1.