Fluorescence excitation spectrum of the tert-butoxy radical and kinetics of its reactions with NO and NO2
Abstract
The
fluorescence ) (tert-butoxy) radical in the wavelength range 330–440
nm was obtained using a combined laser photolysis/laser-induced fluorescence (
CO′=(515±10) cm−1. The transition origin was assigned at
00=(25836±10) cm−1
[λ00=(387.06±0.15) nm]. The kinetics
of the reactions of the tert-butoxy radical with NO and NO2 over the temperature range T=223–305 K
and pressure range p=5–80 Torr were determined. The rate coefficients for both reactions were
found to be independent of total pressure with kNO=(2.9±0.2)×10−11 cm3 s−1 (5–80 Torr) and kNO2=(2.50±0.2)×10−11
cm3 s−1 (5–80 Torr) at T=295 K. The Arrhenius expressions for the reactions of tert-butoxy
with NO and NO2 were determined to be kNO=(7.6±1.2)×10−12
exp[(3.2±0.8) kJ mol−1/RT] cm3 s−1
and kNO2=(3.5±1.2)×10−12 exp[(4.6±0.7) kJ mol−1/RT] cm3 s−1. Additionally, the radiative lifetime
of the tert-C4H9O(Ã) radical after excitation at λ=341.576 nm was determined to be τrad[tert-C4H9O(Ã)]
(1.5±0.1)
μs. The