Karashima S, Humeniuk A, Suzuki T. Vibrational Motions in Ultrafast Electronic Relaxation of Pyrazine.
J Am Chem Soc 2024. [PMID:
38621175 DOI:
10.1021/jacs.4c02886]
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Abstract
Ultrafast internal conversion via a conical intersection is ubiquitous in highly efficient photochemical reactions. Internal conversion from the 1ππ* to the 1nπ* state of pyrazine is the paradigm for this phenomenon; however, the relaxation occurs in such a short time (<20 fs) that the nuclear motion is difficult to observe in real time. The present study precisely measures the vibrational coherence transferred from the 1ππ* state to the 1nπ* state using time-resolved photoelectron spectroscopy with an unprecedented time resolution of 13.3 fs and reveals the key nuclear motions that drive the internal conversion.
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