Electronic dynamics created at conical intersections and its dephasing in aqueous solution

• Published in: Nature physics 2025-01, Vol.21 (1), p.137-145
• Main Authors: Chang, Yi-Ping, Balciunas, Tadas, Yin, Zhong, Sapunar, Marin, Tenorio, Bruno N. C., Paul, Alexander C., Tsuru, Shota, Koch, Henrik, Wolf, Jean-Pierre, Coriani, Sonia, Wörner, Hans Jakob
• Format: Article
• Language: English
• Subjects: 639/766/36/1121; 639/766/36/1122; Aqueous solutions; Aromatic compounds; Atomic; Classical and Continuum Physics; Complex Systems; Condensed Matter Physics; Electronic structure; Mathematical and Computational Physics; Molecular; Molecular dynamics; Optical and Plasma Physics; Physics; Physics and Astronomy; Pyrazines; Solvation; Spectrum analysis; Theoretical; X-ray spectroscopy
• ISSN: 1745-2473; 1745-2481
• DOI: 10.1038/s41567-024-02703-w

A dynamical rearrangement in the electronic structure of a molecule can be driven by different phenomena, including nuclear motion, electronic coherence or electron correlation. Recording such electronic dynamics and identifying its fate in an aqueous solution has remained a challenge. Here, we reveal the electronic dynamics induced by electronic relaxation through conical intersections in both isolated and solvated pyrazine molecules using X-ray spectroscopy. We show that the ensuing created dynamics corresponds to a cyclic rearrangement of the electronic structure around the aromatic ring. Furthermore, we found that such electronic dynamics were entirely suppressed when pyrazine was dissolved in water. Our observations confirm that conical intersections can create electronic dynamics that are not directly excited by the pump pulse and that aqueous solvation can dephase them in less than 40 fs. These results have implications for the investigation of electronic dynamics created during light-induced molecular dynamics and shed light on their susceptibility to aqueous solvation. Tracking ultrafast electronic changes in molecules is challenging, especially in liquids. An X-ray spectroscopy study in pyrazine now shows electronic dynamics created at conical intersections that are rapidly suppressed when the molecule is in water.