Timmers Henry, Zhu Xiaolei, Li Zheng, Kobayashi Yuki, Sabbar Mazyar, Hollstein Maximilian, Reduzzi Maurizio, Martínez Todd J, Neumark Daniel M, Leone Stephen R
Department of Chemistry, University of California, Berkeley, CA, 94720, USA.
Department of Chemistry and The PULSE Institute, Stanford University, Stanford, CA, 94305, USA.
Nat Commun. 2019 Jul 16;10(1):3133. doi: 10.1038/s41467-019-10789-7.
Attosecond probing of core-level electronic transitions provides a sensitive tool for studying valence molecular dynamics with atomic, state, and charge specificity. In this report, we employ attosecond transient absorption spectroscopy to follow the valence dynamics of strong-field initiated processes in methyl bromide. By probing the 3d core-to-valence transition, we resolve the strong field excitation and ensuing fragmentation of the neutral σ* excited states of methyl bromide. The results provide a clear signature of the non-adiabatic passage of the excited state wavepacket through a conical intersection. We additionally observe competing, strong field initiated processes arising in both the ground state and ionized molecule corresponding to vibrational and spin-orbit motion, respectively. The demonstrated ability to resolve simultaneous dynamics with few-femtosecond resolution presents a clear path forward in the implementation of attosecond XUV spectroscopy as a general tool for probing competing and complex molecular phenomena with unmatched temporal resolution.
阿秒级对芯能级电子跃迁的探测为研究具有原子、态和电荷特异性的价分子动力学提供了一种灵敏的工具。在本报告中，我们采用阿秒瞬态吸收光谱法来跟踪溴甲烷中强场引发过程的价动力学。通过探测3d芯到价的跃迁，我们解析了溴甲烷中性σ*激发态的强场激发及随后的碎片化过程。结果提供了激发态波包通过锥形交叉点的非绝热通道的清晰特征。我们还观察到分别对应于振动和自旋轨道运动的、在基态和电离分子中产生的相互竞争的强场引发过程。所展示的以飞秒级分辨率解析同时发生的动力学过程的能力，为将阿秒极紫外光谱法作为一种以无与伦比的时间分辨率探测相互竞争和复杂分子现象的通用工具的实施提供了一条清晰的前进道路。
