Rate coefficients for the reactions of C(3PJ) atoms with C2H2, C2H4, CH3C=CHand H2C=C=CH2 at temperatures down to 15 K
Rate coefficients for the reactions of C(3PJ) atoms with C2H2, C2H4, CH3C=CHand H2C=C=CH2 at temperatures down to 15 K
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DOI：
10.1051/0004-6361:20000026
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发表时间：
2001-01-01
影响因子：
6.5
通讯作者：
Smith, IWM
中科院分区：
文献类型：
--
作者：
Chastaing, D;Le Picard, SD;Smith, IWM
在15K以下测量了基态碳原子C(P-3(J))与四种不饱和碳氢化合物C_2H_2、C_2H_4、CH_3C=CH和H_2C=C=CH_2反应的速率系数。实验在连续排CRESU(Cinetique De Reaction En Ecoulement Suffique Uniformme)装置上进行，用脉冲激光光解C_3O_2产生C(P-3(J))原子，并在真空紫外光下用激光诱导荧光观察原子的动力学衰变，从而测定速率系数。研究发现，所有四个反应的发生速率都接近碰撞决定的极限，并且这些速率对温度的依赖程度至多是非常温和的。通常情况下，这些反应沿着无障碍的反应路径进行，形成一个强结合的带电加合物，随后消除一个H原子形成反应产物。讨论了C(P-3(J))原子与较大的不饱和烃的反应速率。最后，我们考虑了这些结果与致密星际云化学的相关性。
Rate coefficients for the reactions of ground state carbon atoms, C(P-3(J)), With the four unsaturated hydrocarbons C2H2, C2H4, CH3C = CH and H2C = C = CH2 have been measured at temperatures down to 15 K. The experiments have been performed in a continuous Row CRESU (Cinetique de Reaction en Ecoulement Supersonique Uniforme) apparatus using pulsed laser photolysis of C3O2 to generate C(P-3(J)) atoms and laser-induced fluorescence in the vacuum ultraviolet to observe the kinetic decays of the atoms and hence deter mine the rate coefficients. All four reactions are found to occur at rates close to the collision-determined limit and the rates show at most a very mild dependence on temperature. It is argued that normally these reactions proceed along a reaction path with no barrier to form a strongly bound energised adduct, which subsequently eliminates an H atom to form the reaction products. The rates of the reactions of C(P-3(J)) atoms with larger unsaturated hydrocarbons are discussed. Finally, the relevance of the results for the chemistry of dense interstellar clouds is considered.