Horio Takuya, Spesyvtsev Roman, Nagashima Kazuki, Ingle Rebecca A, Suzuki Yoshi-Ichi, Suzuki Toshinori
Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-Ku, Kyoto 606-8502, Japan.
J Chem Phys. 2016 Jul 28;145(4):044306. doi: 10.1063/1.4955296.
A photoexcited molecule undergoes multiple deactivation and reaction processes simultaneously or sequentially, which have been observed by combinations of various experimental methods. However, a single experimental method that enables complete observation of the photo-induced dynamics would be of great assistance for such studies. Here we report a full observation of cascaded electronic dephasing from S2(ππ()) in pyrazine (C4N2H4) by time-resolved photoelectron imaging (TRPEI) using 9.3-eV vacuum ultraviolet pulses with a sub-20 fs time duration. While we previously demonstrated a real-time observation of the ultrafast S2(ππ()) → S1(nπ()) internal conversion in pyrazine using TRPEI with UV pulses, this study presents a complete observation of the dynamics including radiationless transitions from S1 to S0 (internal conversion) and T1(nπ()) (intersystem crossing). Also discussed are the role of (1)Au(nπ()) in the internal conversion and the configuration interaction of the S2(ππ()) electronic wave function.
一个光激发分子会同时或依次经历多个失活和反应过程，这些过程已通过各种实验方法的组合被观测到。然而，一种能够完整观测光诱导动力学的单一实验方法将对这类研究有很大帮助。在此，我们报告了利用持续时间低于20飞秒的9.3电子伏特真空紫外脉冲，通过时间分辨光电子成像（TRPEI）对吡嗪（C4N2H4）中从S2(ππ())开始的级联电子退相进行的完整观测。虽然我们之前利用紫外脉冲的TRPEI展示了对吡嗪中超快S2(ππ())→S1(nπ())内转换的实时观测，但本研究展示了对包括从S1到S0的无辐射跃迁（内转换）以及T1(nπ())（系间窜越）在内的动力学的完整观测。还讨论了(1)Au(nπ())在S2(ππ())电子波函数的内转换和组态相互作用中的作用。
