Effect of dynamic correlation on the ultrafast relaxation of uracil in the gas phase

Chakraborty, Pratip, Liu, Yusong, Weinacht, Thomas and Matsika, Spiridoula (2021) Effect of dynamic correlation on the ultrafast relaxation of uracil in the gas phase. Faraday Discussions, 228. pp. 266-285. ISSN 1364-5498

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Abstract

The photophysics and photochemistry of DNA/RNA nucleobases have been extensively investigated during the past two decades, both experimentally and theoretically. The ultrafast relaxation of the canonical nucleobases following photoexcitation is of significant interest when it comes to understanding how nature has ensured their photostability. Here we study the excited state dynamics of uracil which is a nucleobase found in RNA. Although theory and experiment have shed significant light on understanding the photoexcited dynamics of uracil, there are still disagreements in the literature about specific details. In order to examine how the dynamics is influenced by the underlying electronic structure theory, we have performed non-adiabatic excited state dynamics simulations of uracil using on-the-fly trajectory surface hopping methodology on potential energy surfaces calculated at different electronic structure theory levels (CASSCF, MRCIS, XMS-CASPT2, TD-DFT). These simulations reveal that the dynamics are very sensitive to the underlying electronic structure theory, with the multi-reference theory levels that include dynamic correlation, predicting that there is no trapping on the absorbing S2 state, in contrast to predictions from lower level electronic structure results. The dynamics are instead governed by ultrafast decay to the ground state, or trapping on the dark S1 state.

Item Type:	Article
Additional Information:	Acknowledgements: The authors gratefully acknowledge the Department of Energy (DOE, Award No. DE-FG02-08ER15983 for P. C. and S. M. and DOE, Award No. DE-FG02-08ER15984 for Y. L. and T. W.) for funding. Most of the computational work was performed using the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by the National Science Foundation Grant No. ACI-1548562. P. C. thanks Asst. Prof. Jae Woo Park and XSEDE personnel for technical advice/help with running jobs and installation of Bagel package, and Dr Sebastian Mai for general advice on trajectory surface hopping.
Faculty \ School:	Faculty of Science > School of Chemistry, Pharmacy and Pharmacology
Related URLs:	http://www.scopus.com/inward/record.url?...
Depositing User:	LivePure Connector
Date Deposited:	29 Sep 2025 09:30
Last Modified:	21 Oct 2025 22:31
URI:	https://ueaeprints.uea.ac.uk/id/eprint/100480
DOI:	10.1039/D0FD00110D

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