Session D11: Focus Session: Promises and Challenges in Chemical Dynamics III

2:30 PM–5:18 PM, Monday, March 13, 2006
Baltimore Convention Center Room: 303

Sponsoring Unit: DCP
Chair: Laurie Butler, University of Chicago

Abstract ID: BAPS.2006.MAR.D11.9

Abstract: D11.00009 : Determining the Products and Mechanism of the C$_{2}$Cl$_{3}$+O$_{2}$ Reaction by Time-Resolved FTIR Emission Spectroscopy

4:30 PM–4:42 PM

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Authors:

  Hongmei Su
  Tiancheng Xiang
  Shaolei Zhao
  Congyun Shi

The reaction products and mechanism of the C$_{2}$Cl$_{3}$ radical with O$_{2}$ have been studied by time-resolved FTIR emission spectroscopy. The chlorinated vinyl radical, C$_{2}$Cl$_{3}$, was generated by 248 nm photolysis of a C$_{2}$Cl$_{4}$ precursor. Vibrationally excited CO, CO$_{2}$ and ClCO products were observed. The time evolution of the emission intensity shows that CO$_{2}$ and ClCO are primary reaction products. In contrast, CO emission does not decay until \textit{ms} time scale indicating that CO products are due to secondary reactions, most likely, the further dissociation of ClCO. Two primary reaction channels are identified: C$_{2}$Cl$_{3}$ + O$_{2} \quad \diamondsuit $ CO$_{2}$ + CCl$_{3}$ $\diamondsuit $ ClCO + COCl$_{2}$ When reacting with O$_{2}$, the observed products and channels of the chlorinated vinyl radical, C$_{2}$Cl$_{3}$, turned out to be very similar to its counterpart, vinyl radical C$_{2}$H$_{3}$. Morokuma's DFT study$^{[1]}$ of the reaction C$_{2}$H$_{3}$+O$_{2}$ shows that the main reaction path proceeds through a three-membered CCO ring adduct. The question is, does C$_{2}$Cl$_{3}$ go through the same reaction path as C$_{2}$H$_{3}$? Does the substitution of H atom by heavier Cl atom make any difference in regard to the reaction mechanism? Further investigation combining \textit{ab initio }calculation is under way. \newline \newline [1] A.M.Mabel, E.W.G.Diau, M.C.Lin, and K.Morokuma, J.Am.Chem.Soc. 118, 9759 (1996)

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2006.MAR.D11.9