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 al 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.%运用脉冲激光光解-激光诱导荧光(PLP-LIF)的方法在298-673 K的温度范围内测量了C2(a3Пu)自由基与含硫小分子(H2S, SO2, CS2)气相反应的双分子反应速率常数.获得的速率常数可以用 Arrhenius 公式表达如下(单位： cm3∙molecule-1∙s-1)： 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]；误差为2σ.由获得的双分子速率常数及所表现的正温度效应,认为 C2(a3Пu)与 H2S 反应遵循抽氢反应机理； C2(a3Пu)与 SO2反应是无能垒的过程,反应速率表现出强的负温度依赖关系；根据较大的双分子速率常数及其呈现的负温度效应我们认为, C2(a3Пu)与CS2反应遵循加成反应机理.
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