Ultrafast valence to non-valence excited state dynamics in a common anionic chromophore

Bull, James N.; Anstöter, Cate S.; Verlet, Jan R.R.

Abstract

Non-valence states in neutral molecules (Rydberg states) have well-established roles and importance in photochemistry, however, considerably less is known about the role of non-valence states in photo-induced processes in anions. Here, femtosecond time-resolved photoelectron imaging is used to show that photoexcitation of the S1(ππ*) state of the methyl ester of deprotonated para-coumaric acid – a model chromophore for photoactive yellow protein (PYP) – leads to a bifurcation of the excited state wavepacket. One part remains on the S1(ππ*) state forming a twisted intermediate, whilst a second part leads to the formation of a non-valence (dipole-bound) state. Both populations eventually decay independently by vibrational autodetachment. Valence-to-non-valence internal conversion has hitherto not been observed in the intramolecular photophysics of an isolated anion, raising questions into how common such processes might be, given that many anionic chromophores have bright valence states near the detachment threshold.

Citation

Bull, J. N., Anstöter, C. S., & Verlet, J. R. (2019). Ultrafast valence to non-valence excited state dynamics in a common anionic chromophore. Nature Communications, 10(1), Article 5820. https://doi.org/10.1038/s41467-019-13819-6

• Journal Article Type: Article
• Acceptance Date: Nov 27, 2019
• Online Publication Date: Dec 20, 2019
• Publication Date: Dec 20, 2019
• Deposit Date: Jan 2, 2020
• Publicly Available Date: Jan 2, 2020
• Journal: Nature Communications
• Electronic ISSN: 2041-1723
• Publisher: Nature Research
• Peer Reviewed: Peer Reviewed
• Volume: 10
• Issue: 1
• Article Number: 5820
• DOI: https://doi.org/10.1038/s41467-019-13819-6
• Public URL: https://durham-repository.worktribe.com/output/1280321