Costen Matthew L, Hall Gregory E
Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
Phys Chem Chem Phys. 2005 Apr 7;7(7):1408-13. doi: 10.1039/b419006h.
Using Doppler-resolved transient frequency modulation absorption spectroscopy, we have measured both alignment and orientation quantum beats arising from nuclear hyperfine depolarization of low rotational levels of CN X 2sigma+ photofragments produced in the ultraviolet photodissociation of ICN. Under our conditions of fully resolved fine-structure and completely unresolved hyperfine structure, the observed time evolution is insensitive to the rapid depolarization of angular momentum N that would be observed if the fine-structure components were not resolved. Non-statistical spin-rotation populations of CN photofragments, previously observed only for high rotational states, are now observed even for the lowest rotational states, indicating that the electron can not be considered a spectator spin in the depolarization.
利用多普勒分辨瞬态频率调制吸收光谱，我们测量了在ICN的紫外光解离过程中产生的CN X 2σ⁺光碎片低转动能级的核超精细退极化所引起的取向和排列量子拍。在我们完全分辨精细结构且完全未分辨超精细结构的条件下，观测到的时间演化对视角动量N的快速退极化不敏感，如果精细结构分量未被分辨，就会观测到这种快速退极化。以前仅在高转动态中观测到的CN光碎片的非统计自旋 - 转动布居，现在甚至在最低转动态中也被观测到，这表明在退极化过程中电子不能被视为旁观者自旋。
