A combined crossed-beam, ab initio, and Rice-Ramsperger-Kassel-Marcus investigation of the reaction of carbon atoms C(3Pj) with benzene, C6H6(X 1A1g) and d6-benzene, C6D6(X 1A1g)
A combined crossed-beam, ab initio, and Rice-Ramsperger-Kassel-Marcus investigation of the reaction of carbon atoms C(3Pj) with benzene, C6H6(X 1A1g) and d6-benzene, C6D6(X 1A1g)
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DOI：
10.1063/1.1418744
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发表时间：
2002-02-22
影响因子：
4.4
通讯作者：
Schaefer, HF
中科院分区：
文献类型：
--
作者：
Hahndorf, I;Lee, YT;Schaefer, HF
利用交叉分子束技术，在8.8 ~ 52.5kJ mol（-1）的12个碰撞能下，研究了C（P-3（j））与苯（C6 H6）（X（1）A（1g））和d（6）-苯（C6 D 6）（X（1）A（1g））的反应.前向卷积拟合的数据，高层次的电子结构计算，和Rice-Ramsperger-Kassel-Marcus（RRKM）调查的单重态和三重态C7 H6/C7 D 6势能超面表明，在低碰撞能量的化学反应动力学是间接的，并占主导地位的大的影响参数。随着碰撞能量的增加，较小的碰撞参数变得更加重要，化学动力学也越来越直接。在所有碰撞能量下，反应在三重态表面上进行，通过碳原子的无屏障加成形成双环中间体，然后将初始碰撞复合物开环为七元环中间体（环庚三烯叉基）。后者在没有出口势垒的情况下分解成化学上不太稳定的1，2-二脱氢环庚三烯基自由基C7 H5（（XB 1）-B-2）+H及其氘代C7 D5（（XB 1）-B-2）+D对应物。观察到C7 D 6加合物的形成作为第二通道。苯的破坏的无障碍路线可以帮助模拟在星际介质中合成高级多环芳烃衍生物的重要途径，在垂死的碳恒星的流出物中，在富含碳氢化合物的行星大气中，以及在贫氧燃烧火焰中。(C)2002年美国物理学会。
The reactions of atomic carbon, C(P-3(j)), with benzene, C6H6(X (1)A(1g)), and with d(6)-benzene, C6D6(X (1)A(1g)) were investigated at twelve collision energies between 8.8 and 52.5 kJ mol(-1) using the crossed molecular beams technique. Forward-convolution fitting of the data, high-level electronic structure calculations, and Rice-Ramsperger-Kassel-Marcus (RRKM) investigations on the singlet and triplet C7H6/C7D6 potential energy hyperface suggest that at low collision energies the chemical reaction dynamics are indirect and dominated by large impact parameters. As the collision energy increases, smaller impact parameters become more important, and the chemical dynamics is increasingly direct. At all collision energies, the reaction proceeds on the triplet surface via a barrierless addition of the carbon atom to form a bicyclic intermediate followed by ring opening of the initial collision complex to a seven-membered ring intermediate (cycloheptatrienylidene). The latter decomposes without exit barrier to the thermodynamically less stable 1,2-didehydrocycloheptatrienyl radical, C7H5((XB1)-B-2)+H, and its deuterated C7D5((XB1)-B-2)+D counterpart. The formation of a C7D6 adduct is observed as a second channel. The barrierless route for the destruction of benzene can help to model important pathways for the synthesis of higher polycyclic aromatic hydrocarbon derivatives in the interstellar medium, in outflows of dying carbon stars, in hydrocarbon-rich planetary atmospheres, as well as in oxygen-poor combustion flames. (C) 2002 American Institute of Physics.