Ultrafast nonradiative transition pathways in photo-excited pyrazine: Ab initio analysis of time-resolved vacuum ultraviolet photoelectron spectrum
| Autor: | Françoise Remacle, Manabu Kanno, Yuichi Fujimura, Hirohiko Kono, Noriyuki Shimakura, Benoît Mignolet, Shiro Koseki |
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| Rok vydání: | 2018 |
| Předmět: |
010304 chemical physics
Pyrazine Photoemission spectroscopy Ab initio General Physics and Astronomy Conical intersection 010402 general chemistry 01 natural sciences Spectral line 0104 chemical sciences chemistry.chemical_compound Internal conversion chemistry Excited state Ionization 0103 physical sciences Physical and Theoretical Chemistry Atomic physics |
| Zdroj: | Chemical Physics. 515:704-709 |
| ISSN: | 0301-0104 |
| DOI: | 10.1016/j.chemphys.2018.07.015 |
| Popis: | The internal conversion of photo-excited pyrazine, which occurs rapidly on a time scale of about 20 fs, has long been considered to proceed via a conical intersection between the optically bright S2 (1B2u, ππ∗) and dark S1 (1B3u, nπ∗) states. Since 2008, several theoretical studies have raised the possibility that other dark states S3 (1Au, nπ∗) and S4 (1B2g, nπ∗) may participate dominantly in the early stage of the nonradiative decay of S2. To clarify this issue, being motivated by the recent pump–probe experiment by Horio et al. [J. Chem. Phys. 145 (2016) 044306], we calculated vacuum ultraviolet photoelectron spectra for ionization from each of the four excited states. Comparison was made with the measured time-resolved photoelectron spectrum exhibiting a temporally varying multi-band structure. We confirmed no contribution of S3 or S4 and thus the validity of the conventional two-state (S2 → S1) picture for ultrafast nonradiative transition in pyrazine. |
| Databáze: | OpenAIRE |
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