CHEMICAL KINETIC-STUDIES USING ULTRAVIOLET CAVITY RING-DOWN SPECTROSCOPIC DETECTION - SELF-REACTION OF ETHYL AND ETHYLPEROXY RADICALS AND THE REACTION O-2-]C2H5O2(C2H5)
Db. Atkinson et Jw. Hudgens, CHEMICAL KINETIC-STUDIES USING ULTRAVIOLET CAVITY RING-DOWN SPECTROSCOPIC DETECTION - SELF-REACTION OF ETHYL AND ETHYLPEROXY RADICALS AND THE REACTION O-2-]C2H5O2(C2H5), The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, 101(21), 1997, pp. 3901-3909
A laser photolysis reactor that uses cavity ring-down spectroscopic (C
RDS) detection was characterized and used to measure the rate coeffici
ents of three benchmark reactions of known importance to ethane oxidat
ion. At 295 K and approximately 700 Pa (5.5 Torr) total pressure, we o
btained the self-reaction rate coefficients of k = (1.99 +/- 0.44) x 1
0(-11) cm(3) molecule(-1) s(-1) for C2H5 + C2H5 and k = (7.26 +/- 2.4)
x 10(-14) cm(3) molecule(-1) s(-1) for C2H5O2 + C2H5O2 We obtained k
= (2.7 +/- 0.3) x 10(-12) cm(3) molecule(-1) s(-1) for the pseudo-firs
t-order association reaction O-2 + C2H5 + AT We also measured the abso
rption cross sections of the ethyl radical, sigma(220) = (252 +/- 42)
x 10(-20) cm(2) molecule(-1) and sigma(222) 2 (206 +/- 42) x 10(-20) c
m(2) molecule(-1) Stated uncertainties are 2 sigma. The new rate coeff
icients agree with those obtained previously by other methods. The agr
eement confirms that ultraviolet CRDS detection is a viable tool for e
xperimental determinations of gas-phase radical-radical and radical-mo
lecule reaction late coefficients.