以飞秒 40 0及 2 66nm激光脉冲结合泵浦 探测飞行时间质谱方法研究了苯S2 态内转换动力学 .40 0nm双光子过程将苯分子激发到S2 电子态 ,布居在S2 电子态的分子由于能级耦合无辐射弛豫到S1电子态 .通过测定C6 H6 +讯号强度随泵浦 探测延迟时间的改变 ,获得苯S2 及S1电子态的衰减寿命分别为 ( 48± 1)fs及 ( 6.5± 0 .2 )ps ,S2 态及S1电子态的消激发机理被认为是相应势能面间的锥形交叉引起的内转换 The kinetics of benzene S2 state transition was studied by using 40s and 266nm femtosecond laser pulses combined with pump-time-of-flight mass spectrometry. Two-photon photons of 400 nm excited benzene molecules to the S2 electron state. The molecules residing in the S2 electron state The decay lifetimes of benzene S2 and S1 electronic states were (48 ± 1) fs and (6.5), respectively, due to the coupling of energy level relaxation to the S1 electron state by measuring the signal intensity of C6 H6 + ± 0 .2) The extinction mechanism of ps, S2 states and S1 electronic states is considered as the internal transition caused by the conical intersection between the corresponding potential surfaces