Lin Ming-Fu, Dyakov Yuri A, Lin Sheng Hsien, Lee Yuan T, Ni Chi-Kung
Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei, Taiwan.
J Phys Chem B. 2005 May 5;109(17):8344-9. doi: 10.1021/jp047647g.
Photodissociation of fluorine-substituted benzenes, including 1,3-difluorobenzene, 1,2,4-trifluorobenzene, 1,2,4,5-tetrafluorobenzene, and pentafluorobenzene, at 193 nm under collision-free conditions has been studied in separate experiments using multimass ion imaging techniques. HF elimination was found to be the major dissociation channel for all of these molecules. Small amounts of photofragments of C(6)H(3)F(2) and C(6)H(2)F(3) from 1,3-difluorobenzene and 1,2,4-trifluorobenzene, respectively, were also observed. They correspond to the minor dissociation channel of hydrogen elimination. Dissociation rates and fragment translational energy distributions obtained from experimental measurements suggest that HF and hydrogen elimination reactions occur in the ground electronic state. The potential energy surface obtained from ab initio calculations indicates that the four-center reaction in the ground electronic state is the major dissociation mechanism for the HF eliminations. A comparison with the RRKM calculation has been made.
在无碰撞条件下，利用多质量离子成像技术，通过单独实验研究了氟代苯（包括1,3 - 二氟苯、1,2,4 - 三氟苯、1,2,4,5 - 四氟苯和五氟苯）在193 nm处的光解离。发现HF消除是所有这些分子的主要解离通道。还分别观察到来自1,3 - 二氟苯和1,2,4 - 三氟苯的少量C(6)H(3)F(2)和C(6)H(2)F(3)光碎片。它们对应于氢消除的次要解离通道。从实验测量获得的解离速率和碎片平动能分布表明，HF和氢消除反应在基电子态发生。从头算计算得到的势能面表明，基电子态的四中心反应是HF消除的主要解离机制。已与RRKM计算进行了比较。
