Kinetics of the cyclohexadienyl radical self-reaction and oxidation reaction using cavity ring-down spectroscopy

摘要

Visible absorption spectra of the cyclohexadienyl radical (с-C_6H_7) assigned to the _ _ X electronic tran_sition have been measured using laser photolysis coupled with a cavity ring-down spectroscopic detec_tion technique. Spectral simulation of the rotational structure of an origin band at room temperature was performed using molecular constants predicted by quantum chemical calculations. Pressure dependence of the self-reaction of the cyclohexadienyl radical was measured in the pressure range of 10-100 Torr. The reaction rate coefficient of the cyclohexadienyl radical with molecular oxygen at 10 Torr N2 buffer and room temperature was determined to be (5.4 ± 0.7) x 10~-14 cm~3 molecule~-1 s~-1, which is in good agreement with previous reported value measured at 760 Torr.