6994 J. Phys. Chem. A, Vol. 114, No. 26, 2010
Noell et al.
(6) Paulot, F.; Crounse, J. D.; Kjaergaard, H. G.; Kurten, A.; St Clair,
J. M.; Seinfeld, J. H.; Wennberg, P. O. Science 2009, 325, 730.
(7) Rudolph, J. J. Geophys. Res., [Atmos.] 1995, 100, 11369.
(8) Boyd, A. A.; Flaud, P. M.; Daugey, N.; Lesclaux, R. J. Phys. Chem.
A. 2003, 107, 818.
(9) Cattell, F. C.; Cavanagh, J.; Cox, R. A.; Jenkin, M. E. J. Chem.
Soc., Faraday Trans. 2 1986, 82, 1999.
(10) Dagaut, P.; Wallington, T. J.; Kurylo, M. J. J. Phys. Chem. 1988,
92, 3836.
(11) Fenter, F. F.; Catoire, V.; Lesclaux, R.; Lightfoot, P. D. J. Phys.
Chem. 1993, 97, 3530.
(12) Maricq, M. M.; Szente, J. J. J. Phys. Chem. 1994, 98, 2078.
(13) Raventos-Duran, M. T.; Percival, C. J.; McGillen, M. R.; Hamer,
P. D.; Shallcross, D. E. Phys. Chem. Chem. Phys. 2007, 9, 4338.
(14) Adachi, H.; Basco, N. Chem. Phys. Lett. 1979, 64, 431.
(15) Anastasi, C.; Waddington, D. J.; Woolley, A. J. Chem. Soc.,
Faraday Trans. 1983, 79, 505.
(16) Andersson, B. Y.; Cox, R. A.; Jenkin, M. E. Int. J. Chem. Kinet.
1988, 20, 283.
(17) Tang, Y. X.; Tyndall, G. S.; Orlando, J. J. J. Phys. Chem. A. 2010,
114, 369.
(18) Stone, D.; Rowley, D. M. Phys. Chem. Chem. Phys. 2005, 7, 2156.
(19) Anastasi, C. B. M. J.; Smith, D. B.; Waddington, D. J. Joint Meeting
of the French and Italian Sections of the Combustion Institute, June 1987,
Amalfi.
(20) Atkinson, D. B.; Hudgens, J. W. J. Phys. Chem. A 1997, 101, 3901.
(21) Bauer, D.; Crowley, J. N.; Moortgat, G. K. J. Photochem.
Photobiol., A 1992, 65, 329.
(22) Fauvet, S.; Ganne, J. P.; Brion, J.; Daumont, D.; Malicet, J.; Chakir,
A. J. Chim. Phys. Phys.-Chim. Biol. 1997, 94, 484.
(23) Munk, J.; Pagsberg, P.; Ratajczak, E.; Sillesen, A. J. Phys. Chem.
1986, 90, 2752.
experiments. Lastly, from the variation in rate coefficients, and
their temperature dependences, between the CH3O2 and C2H5O2
self-reactions (∼4.5 × 10-13 and ∼1.5 × 10-13), it is clear that
work on different examples of RO2 are needed to understand
the mechanism of the self-reaction and shed light on the variety
of kinetics measured.
Conclusion
The kinetics of the C2H5O2 reaction system, including k2, k3obs
,
k3, and R, were measured using simultaneous independent
detection of the C2H5O2 and HO2 radicals. WM NIR spectros-
copy allowed for sensitive and specific detection of HO2 while
UV absorption was used to monitor C2H5O2. The first direct
measurements of k3 and R were made, and their sensitivity to
k2 was established. Self-consistency established between all the
measured parameters provided confidence in the measurements
and helped determine the overall uncertainty in each. The
experiments on the atmospherically important k2 added to the
growing consensus on the mechanism and overall rate constant
for this reaction with an Arrhenius expression
638 ( 73
k (T) ) 6.01+1.95 × 10-13 exp
cm3 molecules-1 s-1
(
)
2
-1.47
(
)
T
(24) Wallington, T. J.; Dagaut, P.; Kurylo, M. J. J. Photochem.
Photobiol., A 1988, 42, 173.
(25) Kaiser, E. W.; Rimai, L.; Wallington, T. J. J. Phys. Chem. 1989,
93, 4094.
Meanwhile the measurements of k3 and R provided strikingly
different results than those obtained previously
(26) Niki, H.; Maker, P. D.; Savage, C. M.; Breitenbach, L. P. J. Phys.
Chem. 1982, 86, 3825.
(27) Wallington, T. J.; Gierczak, C. A.; Ball, J. C.; Japar, S. M. Int.
J. Chem. Kinet. 1989, 21, 1077.
-23 ( 61
k (T) ) 1.29+0.34 × 10-13 exp
cm3 molecules-1 s-1
(
)
3
-0.27
(
)
T
(28) Lightfoot, P. D.; Cox, R. A.; Crowley, J. N.; Destriau, M.; Hayman,
G. D.; Jenkin, M. E.; Moortgat, G. K.; Zabel, F. Atmos. EnViron., Part A
1992, 26, 1805.
(29) Christensen, L. E.; Okumura, M.; Sander, S. P.; Friedl, R. R.; Miller,
C. E.; Sloan, J. J. J. Phys. Chem. A 2004, 108, 80.
(30) Kaiser, E. W. J. Phys. Chem. 1995, 99, 707.
(31) Clifford, E. P.; Farrell, J. T.; DeSain, J. D.; Taatjes, C. A. J. Phys.
Chem. A 2000, 104, 11549.
and R ) 0.28 ( 0.06 independent of temperature. The difference
in R being especially important given that its literature value is
frequently used as the branching fraction value for all RO2 self-
reactions with R * CH3. It was also the first low temperature
study of R. Both experimental and theoretical verification of k3
and R are needed in order to better understand the self-reactions
of C2H5O2 and the self-reactions of RO2 in general.
(32) Kaiser, E. W.; Lorkovic, I. M.; Wallington, T. J. J. Phys. Chem.
1990, 94, 3352.
(33) DeSain, J. D.; Ho, A. D.; Taatjes, C. A. J. Mol. Spectrosc. 2003,
Acknowledgment. This research was carried out by the Jet
Propulsion Laboratory, California Institute of Technology, under
contract with the National Aeronautics and Space Administration
(NASA). This work was supported by the NASA Upper
Atmosphere Research and Tropospheric Chemistry Programs
and the NASA Graduate Student Research Program (GSRP).
The authors would like to thank Dave Natzic for extensive
laboratory support and Dr. Lance Christensen and the Okumura
group for many discussions.
219, 163.
(34) FACSIMILE, 4.0.36 ed.; MCPA Software Ltd., 2002.
(35) Thiebaud, J.; Crunaire, S.; Fittschen, C. J. Phys. Chem. A 2007,
111, 6959.
(36) Sander, S. P.; Finlayson-Pitts, B. J.; Friedl, R. R.; Golden, D. M.;
Huie, R. E.; Kolb, C. E.; Kurylo, M. J.; Molina, M. J.; Moortgat, G. K.;
Orkin, V. L.; Ravishankara, A. R. JPL 2006: Chemical Kinetics and
Photochemical Data for Use in Atmospheric Studies; Evaluation No. 15,
JPL Publication 06-2, 2006, Jet Propulsion Lab, 2006.
(37) Vaghjiani, G. L.; Ravishankara, A. R. J. Chem. Phys. 1990, 92,
996.
(38) Christensen, L. E.; Okumura, M.; Hansen, J. C.; Sander, S. P.;
Francisco, J. S. J. Phys. Chem. A. 2006, 110, 6948.
(39) Atkinson, R.; Baulch, D. L.; Cox, R. A.; Crowley, J. N.; Hampson,
R. F.; Hynes, R. G.; Jenkin, M. E.; Rossi, M. J.; Troe, J. Atmos. Chem.
Phys. 2006, 6, 3625.
(40) Taatjes, C. A.; Christensen, L. K.; Hurley, M. D.; Wallington, T. J.
J. Phys. Chem. A 1999, 103, 9805.
(41) Wallington, T. J.; Skewes, L. M.; Siegl, W. O.; Wu, C. H.; Japar,
S. M. Int. J. Chem. Kinet. 1988, 20, 867.
(42) Seakins, P. W.; Orlando, J. J.; Tyndall, G. S. Phys. Chem. Chem.
Phys. 2004, 6, 2224.
(43) Horie, O.; Crowley, J. N.; Moortgat, G. K. J. Phys. Chem. 1990,
94, 8198.
(44) Hasson, A. S.; Tyndall, G. S.; Orlando, J. J. J. Phys. Chem. A 2004,
108, 5979.
(45) Spittler, M.; Barnes, I.; Becker, K. H.; Wallington, T. J. Chem.
Note Added after ASAP Publication. This article posted
ASAP on June 4, 2010. Tables 1 and 3 have been revised. The
correction version posted on June 11, 2010.
References and Notes
(1) Christensen, L. E.; Okumura, M.; Sander, S. P.; Salawitch, R. J.;
Toon, G. C.; Sen, B.; Blavier, J. F.; Jucks, K. W. Geophys. Res. Lett. 2002,
29.
(2) Jacob, D. J. Introduction to Atmospheric Chemistry; Princeton
University Press: Princeton, NJ, 1999.
(3) Tyndall, G. S.; Cox, R. A.; Granier, C.; Lesclaux, R.; Moortgat,
G. K.; Pilling, M. J.; Ravishankara, A. R.; Wallington, T. J. J. Geophys.
Res., [Atmos.] 2001, 106, 12157.
(4) Bonn, B.; von Kuhlmann, R.; Lawrence, M. G. Geophys. Res. Lett.
2004, 31.
Phys. Lett. 2000, 321, 57.
(46) Wallington, T. J.; Japar, S. M. Chem. Phys. Lett. 1990, 166, 495.
(47) Elrod, M. J.; Ranschaert, D. L.; Schneider, N. J. Int. J. Chem. Kinet.
2001, 33, 363.
(5) Kroll, J. H.; Ng, N. L.; Murphy, S. M.; Flagan, R. C.; Seinfeld,
J. H. EnViron. Sci. Technol. 2006, 40, 1869.