Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, 606-8502 Kyoto, Japan.
Phys Rev Lett. 2016 Apr 1;116(13):137601. doi: 10.1103/PhysRevLett.116.137601.
We have studied ultrafast nonadiabatic dynamics of excess electrons trapped in the band gap of liquid water using time- and angle-resolved photoemission spectroscopy. Anisotropic photoemission from the first excited state was discovered, which enabled unambiguous identification of nonadiabatic transition to the ground state in 60 fs in H_{2}O and 100 fs in D_{2}O. The photoelectron kinetic energy distribution exhibited a rapid spectral shift in ca. 20 fs, which is ascribed to the librational response of a hydration shell to electronic excitation. Photoemission anisotropy indicates that the electron orbital in the excited state is depolarized in less than 40 fs.
我们使用时间和角度分辨光电子能谱研究了液体水中被陷阱在能带隙中的过剩电子的超快非绝热动力学。我们发现了各向异性的第一激发态光发射，这使得我们能够在 H_{2}O 中在 60fs 和 D_{2}O 中在 100fs 内明确识别到非绝热跃迁到基态。光电子动能分布在大约 20fs 内显示出快速的光谱移动，这归因于电子激发对水合壳的旋转响应。光电子各向异性表明，激发态中的电子轨道在不到 40fs 内被去极化。
