Ultrafast nonradiative transition pathways in photo-excited pyrazine: Ab initio analysis of time-resolved vacuum ultraviolet photoelectron spectrum

Benoît Mignolet, Manabu Kanno, Noriyuki Shimakura, Shiro Koseki, Françoise Remacle, Hirohiko Kono, Yuichi Fujimura

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)704-709
Number of pages6
JournalChemical Physics
Volume515
DOIs
Publication statusPublished - 2018 Nov 14

Keywords

  • Dark states
  • Internal conversion
  • Photoelectron spectrum
  • Pyrazine
  • Vacuum ultraviolet laser

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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