论文标题
高分辨率共振增强的多光子光电子圆二色性
High-resolution resonance-enhanced multiphoton photoelectron circular dichroism
论文作者
论文摘要
光电子圆二色性（PECD）是一种高度敏感的对映体光谱，用于使用单光子电离或多光子离子化研究气相中的手性分子。在使用飞秒激光器调查的短脉冲极限中，由于有限的频率分辨率有限，共振增强的乘积电离（REMPI）相当瞬时，通常通过一个以上的振动或电子中间状态同时发生。相反，可以使用纳秒激光器来实现REMPI光谱中的振动分辨率。在这项工作中，我们使用可调窄带纳秒激光遵循高分辨率方法，通过中间3S和3P rydberg fenchone的振动水平在不同的振动水平上测量REMPI-PECD。我们观察到PECD本质上独立于振动水平。手性敏感性的这种行为可能为在多组分混合物中的对映异构体特异性分子鉴定铺平道路：一个人可以特异性地激发出明确的，振动的分辨分子的尖锐，振动分析的跃迁，以区分混合物中的不同手掌物质。
Photoelectron circular dichroism (PECD) is a highly sensitive enantiospecific spectroscopy for studying chiral molecules in the gas phase using either single-photon ionization or multiphoton ionization. In the short pulse limit investigated with femtosecond lasers, resonance-enhanced multiphoton ionization (REMPI) is rather instantaneous and typically occurs simultaneously via more than one vibrational or electronic intermediate state due to limited frequency resolution. In contrast, vibrational resolution in the REMPI spectrum can be achieved using nanosecond lasers. In this work, we follow the high-resolution approach using a tunable narrow-band nanosecond laser to measure REMPI-PECD through distinct vibrational levels in the intermediate 3s and 3p Rydberg states of fenchone. We observe the PECD to be essentially independent of the vibrational level. This behaviour of the chiral sensitivity may pave the way for enantiomer specific molecular identification in multi-component mixtures: one can specifically excite a sharp, vibrationally resolved transition of a distinct molecule to distinguish different chiral species in mixtures.
