论文标题
通过超快XUV瞬时吸收光谱法揭示烷基碘化物圆锥形交集处的电子状态切换
Revealing electronic state-switching at conical intersections in alkyl iodides by ultrafast XUV transient absorption spectroscopy
论文作者
论文摘要
电子状态之间的圆锥形交集通常决定光激发分子的化学性质。最近开发的超舒服极端紫外线（XUV）脉冲调谐到分子中元素特异性跃迁的来源，可以在圆锥形交叉点上明确检测电子状态转换。在这里，光激发的ISO-丙酰碘和丁基碘化物分子（I-C $ _ {3} $ h $ _ {7} $ _ {7} $ _ {7} $ _ {4} $ _ {4} $ h $ _ {9} $ i）通过圆锥形$^{3} $ q $ _ {0} $/$^{1} $ q $ _ {1} $ spin-Orbit状态通过Ultrafast XUV瞬态吸收测量碘4D核心 - 核心核对价过渡揭示。该技术的电子状态敏感性允许将来自光激发到光产物的分子解离完整映射。在这两个分子中，从圆锥形交叉点，从$^{3} $ q $ _ {0} $状态从$^{3} $ q $ _ {0} $状态转移到$^{3} $ q $ _ {0} $状态下的光激发波数据包的低下100 fs传输中。 The results show how differences in the electronic state-switching of the wave packet in i-C$_{3}$H$_{7}$I and t-C$_{4}$H$_{9}$I directly lead to differences in the photoproduct branching ratio of the two systems.
Conical intersections between electronic states often dictate the chemistry of photoexcited molecules. Recently developed sources of ultrashort extreme ultraviolet (XUV) pulses tuned to element-specific transitions in molecules allow for the unambiguous detection of electronic state-switching at a conical intersection. Here, the fragmentation of photoexcited iso-propyl iodide and tert-butyl iodide molecules (i-C$_{3}$H$_{7}$I and t-C$_{4}$H$_{9}$I) through a conical intersection between $^{3}$Q$_{0}$/$^{1}$Q$_{1}$ spin-orbit states is revealed by ultrafast XUV transient absorption measuring iodine 4d core-to-valence transitions. The electronic state-sensitivity of the technique allows for a complete mapping of molecular dissociation from photoexcitation to photoproducts. In both molecules, the sub-100 fs transfer of a photoexcited wave packet from the $^{3}$Q$_{0}$ state into the $^{1}$Q$_{1}$ state at the conical intersection is captured. The results show how differences in the electronic state-switching of the wave packet in i-C$_{3}$H$_{7}$I and t-C$_{4}$H$_{9}$I directly lead to differences in the photoproduct branching ratio of the two systems.
