Abstract A combined theoretical and experimental study on the fragmentation of the mono-halogenated biphenyls; 2-chlorobiphenyl, 2-bromobiphenyl and 2-iodobiphenyl upon electron impact is presented. The appearance energies of the fragments observed and the energy dependence of their relative cross sections are reported. This is a follow up on our previous report 24 on the influence of the dihedral angle on the ionization energy of these compounds, but here we report the appearance energies and the energy dependence of the relative cross-section for all the major fragments. The appearance energies are compared to quantum mechanical threshold calculations at the coupled cluster level of theory and possible molecular structures and reaction pathways are discussed for the observed m/z ratios. For the loss of the halogen along with 1-2 H the agreement between the experiment and theory is good as reported earlier. However, the discrepancy is considerably larger for the ring rupture channels.

中文翻译：

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单卤代联苯电子碰撞电离和离解的相对截面和表观能

摘要 单卤代联苯裂解的理论与实验相结合的研究；介绍了电子撞击时的 2-氯联苯、2-溴联苯和 2-碘联苯。报告了观察到的碎片的外观能量及其相对横截面的能量依赖性。这是我们之前关于二面角对这些化合物电离能影响的报告 24 的后续报道，但在这里我们报告了所有主要碎片的相对横截面的外观能和能量依赖性。将出现能量与理论的耦合簇水平上的量子力学阈值计算进行比较，并针对观察到的 m/z 比率讨论了可能的分子结构和反应途径。对于卤素和 1-2 H 的损失，实验和理论之间的一致性很好，如前所述。然而，环破裂通道的差异要大得多。