Transient resonant Auger-Meitner spectra of photoexcited thymine

Thomas J A Wolf, Alexander C Paul, Sarai D Folkestad, Rolf H Myhre, James P Cryan, Nora Berrah, Phil H Bucksbaum, Sonia Coriani, Giacomo Coslovich, Raimund Feifel, Todd J Martinez, Stefan P Moeller, Melanie Mucke, Razib Obaid, Oksana Plekan, Richard J Squibb, Henrik Koch, Markus Gühr*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

We present the first investigation of excited state dynamics by resonant Auger-Meitner spectroscopy (also known as resonant Auger spectroscopy) using the nucleobase thymine as an example. Thymine is photoexcited in the UV and probed with X-ray photon energies at and below the oxygen K-edge. After initial photoexcitation to a ππ* excited state, thymine is known to undergo internal conversion to an nπ* excited state with a strong resonance at the oxygen K-edge, red-shifted from the ground state π* resonances of thymine (see our previous study Wolf, et al., Nat. Commun., 2017, 8, 29). We resolve and compare the Auger-Meitner electron spectra associated both with the excited state and ground state resonances, and distinguish participator and spectator decay contributions. Furthermore, we observe simultaneously with the decay of the nπ* state signatures the appearance of additional resonant Auger-Meitner contributions at photon energies between the nπ* state and the ground state resonances. We assign these contributions to population transfer from the nπ* state to a ππ* triplet state via intersystem crossing on the picosecond timescale based on simulations of the X-ray absorption spectra in the vibrationally hot triplet state. Moreover, we identify signatures from the initially excited ππ* singlet state which we have not observed in our previous study.

Original languageEnglish
JournalFaraday Discussions
ISSN1359-6640
DOIs
Publication statusAccepted/In press - 2021

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