Due to the electron correlation, a fast removal of an electron from a molecule may create a coherent superposition of cationic states and in this way initiate pure electronic dynamics in which the hole-charge left by ionization migrates throughout the system on an ultrashort time scale. The coupling to the nuclear motion introduces a decoherence that eventually traps the charge and a crucial question in the field of attochemistry is how long the electronic coherence lasts and which nuclear degrees of freedom are mostly responsible for the decoherence. Here, we report full-dimensional quantum calculations of the concerted electron-nuclear dynamics following outer-valence ionization of propynamide, which reveal that the pure electronic coherences last only 2-3 fs before being destroyed by the nuclear motion. Our analysis shows that the normal modes that are mostly responsible for the fast electronic decoherence are the symmetric in-plane modes. All other modes have little or no effect on the charge migration. This information can be useful to guide the development of reduced dimensionality models for larger systems or the search of molecules with long coherence times.
On the role of rotation-vibration coupling in the spectra of ozone isotopomers
在超球坐标系下，考虑科里奥利耦合效应，建立了精确计算三原子分子振转耦合态的理论框架和计算机程序。简洁的最终公式推导出使用FBR和DVR方法与局部优化的基组和网格的有效组合的哈密顿矩阵的建设。首先，新的代码进行了测试，通过比较其结果与Kendrick的APH 3D程序。然后，精确计算的振转光谱进行了双取代对称（18 O 16 O 18 O）和不对称（18 O 18 O 16 O）臭氧同位素的总角动量高达J=5。再加上最近报道的单取代对称（16 O 18 O 16 O）和不对称（16 O 16 O 18 O）臭氧同位素异构体的类似数据，这些计算量化的科里奥利耦合效应的作用，在实验室实验和地球大气中观察到的大质量独立的同位素富集臭氧。结果表明，臭氧的Coriolis效应相对较小，这可以通过臭氧分子的转动常数与非对称顶转子行为的偏离、宇称分裂（Λ-加倍）的大小以及非对称与对称臭氧分子的振转配分函数的比值来证明。它的结论是，所有这些特性的同位素质量的影响，因为它们是由分子的整体对称性的影响。因此，科里奥利耦合效应不太可能是臭氧中氧同位素的非质量驱动分馏的原因。
Rotational spectroscopy as a tool to investigate interactions between vibrational polyads in symmetric top molecules: low-lying states $v_8 \le 2$ of methyl cyanide, CH$_3$CN
Measurement of Coherent Vibrational Dynamics with X-ray Transient Absorption Spectroscopy Simultaneously at the Carbon K- and Chlorine L$_{2,3}$- Edges
