Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (5): 797-802.doi: 10.3866/PKU.WHXB201403072


Temperature Dependence of C2(a3Пu) Radical Reactions with Sulfur Bearing Molecules

HU Ren-Zhi1, XIE Pin-Hua1, ZHANG Qun2, SI Fu-Qi1, CHEN Yang2   

  1. 1 Key Laboratory of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Science, Hefei 230031, P. R. China;
    2 Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, P. R. China
  • Received:2013-12-31 Revised:2014-03-07 Published:2014-04-25
  • Contact: HU Ren-Zhi, CHEN Yang;
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (61108031, 21173205), National Key Basic Research Program of China (973) (2010CB923302), and Knowledge Innovation Programs of the Chinese Academy of Sciences (KJCX2-YW-N24).


The bimolecular rate constants for the gas- phase reactions of C2(a3Пu) with sulfur-bearing molecules (H2S, SO2, CS2) were measured over the temperature range 298-673 K, by means of pulsed laser photolysis/laser-induced fluorescence technique. The rate constants (cm3·molecule-1·s-1) can be fitted by the normal Arrhenius expressions: k(H2S)=(1.61±0.06)×10-12exp[-(180.91±15.73)/T], k(SO2)=(1.26±0.10)×10-15 exp[(2230.68±27.77)/T], k(CS2)=(1.17±0.02)×10-10 exp[(253.31±7.69)/T], where all error estimates are ±2σ and represent the precision of the fit. The observed bimolecular rate constants and positive temperature dependence of k(H2S) show that the reaction of C2(a3Пu) with H2S in the range 298-673 K proceeds via a hydrogen-abstraction mechanism. The bimolecular rate constants for the reaction of C2(a3Пu) with SO2 show a strong negative temperature dependence. The high rate constants for the C2(a3Пu)+CS2 reaction and negative temperature dependence support an addition mechanism.

Key words: C2(a3Пu) radical, Laser induced fluorescence, Rate constant, Temperature dependence