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Transient resonant Auger-Meitner spectra of photoexcited thymine.

Authors :
Wolf TJA
Paul AC
Folkestad SD
Myhre RH
Cryan JP
Berrah N
Bucksbaum PH
Coriani S
Coslovich G
Feifel R
Martinez TJ
Moeller SP
Mucke M
Obaid R
Plekan O
Squibb RJ
Koch H
Gühr M
Source :
Faraday discussions [Faraday Discuss] 2021 May 27; Vol. 228 (0), pp. 555-570.
Publication Year :
2021

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.

Details

Language :
English
ISSN :
1364-5498
Volume :
228
Issue :
0
Database :
MEDLINE
Journal :
Faraday discussions
Publication Type :
Academic Journal
Accession number :
33566045
Full Text :
https://doi.org/10.1039/d0fd00112k