中文摘要：

利用CBS—QB3理论计算方法研究了异戊二烯的可能解离通道．获得了主要碎片离子C5H7＋，C5H5＋，C4H5＋，C3H6＋，C3H5＋，C3H4＋，C3H3＋和C2H3＋的结构以及这些解离通道的解离能，并给出了相应的过渡态和中间体的结构和位垒．得到的异戊二烯电离势及主要碎片离子的出现势均与实验值符合的较好．最后，通过理论和实验结果的对比讨论了各通道的解离机理．

英文摘要：

Theoretical calculations have been carried out to investigate the possible dissociation channels of isoprene. We focus on the major fragment ions of C5H7＋, C5H5＋, C4H5＋, C3H6＋, C3H5＋, C3H4＋, C3H3＋ and C2H3＋, which were observed experimentally from the isoprene dissociative photoionization. The energy calculations were performed with the CBS-QB3 model. All the geometries and energies of the fragments, intermediates and transition states involved in the dissociations channels were determined. Finally, the mechanisms of the dissociation pathways were discussed on the comparison of theoretical and experimental results.