Institute of Atomic and Molecular Physics , Jilin University , Changchun 130012 , China.
J Phys Chem A. 2019 Oct 3;123(39):8365-8369. doi: 10.1021/acs.jpca.9b07044. Epub 2019 Sep 20.
Benzene cation is a prototypical complex system that exhibits ultrafast conical intersections of different electronic states located close to the Franck-Condon region, yet little information is available about the dynamics of the cationic excited states. Here we utilize femtosecond time-resolved strong field ionization-photo fragmentation (SFI-PF) method to prepare and probe the electronic states of benzene cations. The transient of both the parent ion and the daughter ions are obtained, which present distinct behaviors at different pulse energies of the SFI laser. The results provide the first experimental evidence of BE-XE ultrafast relaxation of benzene cation, which occurs in about 250-270 fs. Our study should pave the way to revealing the ultrafast photochemistry of complex molecular cations.
苯阳离子是一个典型的复杂体系，它表现出不同电子态的超快锥形交叉，这些交叉位置接近 Franck-Condon 区域，但关于阳离子激发态的动力学信息却很少。在这里，我们利用飞秒时间分辨强场电离-光解（SFI-PF）方法来制备和探测苯阳离子的电子态。获得了母体离子和子离子的瞬态，它们在 SFI 激光的不同脉冲能量下呈现出不同的行为。研究结果提供了苯阳离子 BE-XE 超快弛豫的第一个实验证据，其发生在大约 250-270fs。我们的研究应该为揭示复杂分子阳离子的超快光化学铺平道路。
