1. C 10 H 7 + O 2 C 10 H 7 OO other products J. Park, Hue M. T. Nguyen, # Z. F. Xu and M. C. Lin Department of Chemistry, Emory University, Atlanta, GA 30322 # Present address: Hanoi National University of Education, Hanoi, Vietnam As small aromatic radicals such as phenyl (C 6 H 5 ), phenylvinyl (C 6 H 5 C 2 H 2 ), naphthyl (C 10 H 7 ), and their derivatives are believed to play a pivotal role in the formation of naphthalene (C 10 H 8 ), a possible route to the formation of PAH’s, by HACA (H-Abstraction, C 2 H 2 -Addition) reactions and cyclization reactions. Competing oxidation processes to remove the naphthyl radical, such as C 10 H 7 + O 2, similar to the removal of the phenyl radical by the C 6 H 5 + O 2 reaction, should be quite important to the kinetics of soot formation in its incipient stages. Motivation Motivation DOE Grant No. DE-FG02-97-ER14784. The Cherry L. Emerson Center of Emory University Kinetics of naphthyl (C 10 H 7 ) radical reactions monitored by C 10 H 7 OO Results Results Reaction Mechanism Reaction Mechanism Schematic Diagram of CRDS Schematic Diagram of CRDS 7 th International Conference on Chemical Kinetics, Jul 10 - 14, 2011, Massachusetts Institute of Technology (MIT), Cambridge, MA USA Experimental (CRDS) Experimental (CRDS) The kinetics for the 2-C 10 H 7 + C 2 H 2 reaction has been measured at temperatures 303 - 448 K by indirectly monitoring C 10 H 7 O 2 with the cavity ring- down spectrometry (CRDS) using 2-C 10 H 7 Br as a radical source by photolysis at 193 nm. Computational Computational C 10 H 7 + C 2 H 2 C 10 H 7 C 2 H 2 Optimization and Vibrational Frequency calculation B3LYP/6-311+G(d,p) PES : G2MS//B3LYP/6-311+G(d, p) The microcanonical Rice-Ramsperger-Kassel- Marcus (RRKM) theory was employed to calculate the rate constants of the reactions by VARIFLEX. k 3 = (3.36  0.63)  10 11 exp [-(817  34)/ T] cm 3 mol -1 s -1 Kinetic Modeling Kinetic Modeling 2-C 10 H 7 + C 2 H 2 2-C 10 H 7 = 1-C 10 H 7 2-C 10 H 7 + C 2 H 2 = 2-C 10 H 7 C 2 H 2 2-C 10 H 7 + 2-C 10 H 7 = C 20 H 14 2-C 10 H 7 + O 2 = C 10 H 7 O 2 C 10 H 7 O 2 = others 2-C 10 H 7 C 2 H 2 + O 2 = C 10 H 7 C 2 H 2 O 2 C 10 H 7 C 2 H 2 O 2 = C 10 H 7 CHO + HCO C 10 H 7 C 2 H 2 C 10 H 7 C 2 H + H 1-C 10 H 7 + C 2 H 2 The potential energy surfaces, calculated by G2MS//b3LYP/6-311+G(d,p), show that the reactions of 1- and 2-C 10 H 7 with C 2 H 2 occurs firstly by addition forming the excited naphthyl vinyl radicals, which can undergo isomerization to various structural isomers or elimination of a hydrogen atom by low barrier decomposition channels. The mechanisms for the decomposition of the two radicals were predicted to be significantly different under experimental conditions: the excited 1- C 10 H 7 C 2 H 2 radical produces predominantly acenaphthylene due to its low formation barrier, while the excited 2-C 10 H 7 C 2 H 2 radical can be effectively stabilized by collisional deactivation because of its high exit barrier. Acknowledgement C 10 H 7 C 2 H 2 C 10 H 7 C 2 H + H