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Impact of the Dynamic Electron Correlation on the Unusually Long Excited-State Lifetime of Thymine

Park, Woojin and Lee, Seunghoon and Huix-Rotllant, Miquel and Filatov, Michael and Choi, Cheol Ho (2021) Impact of the Dynamic Electron Correlation on the Unusually Long Excited-State Lifetime of Thymine. Journal of Physical Chemistry Letters, 12 (18). pp. 4339-4346. ISSN 1948-7185. doi:10.1021/acs.jpclett.1c00712.

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Non-radiative relaxation of the photoexcited thymine in the gas phase shows an unusually long excited-state lifetime, and, over the years, a number of models, i.e., S₁-trapping, S₂-trapping, and S₁&S₂-trapping, have been put forward to explain its mechanism. Here, we investigate this mechanism using non-adiabatic molecular dynamics (NAMD) simulations in connection with the recently developed mixed-reference spin-flip time-dependent density functional theory (MRSF-TDDFT) method. We show that the previously predicted S₂-trapping model was due to an artifact caused by an insufficient account of the dynamic electron correlation. The current work supports the S₁-trapping mechanism with two lifetimes, τ₁ = 30 ± 1 fs and τ₂ = 6.1 ± 0.035 ps, quantitatively consistent with the recent time-resolved experiments. Upon excitation to the S₂ (ππ*) state, thymine undergoes an ultrafast (ca. 30 fs) S₂→S₁ internal conversion and resides around the minimum on the S₁ (n₀π*) surface, slowly decaying to the ground state (ca. 6.1 ps). While the S₂→S₁ internal conversion is mediated by fast bond length alternation distortion, the subsequent S₁→S₀ occurs through several conical intersections, involving a slow puckering motion.

Item Type:Article
Related URLs:
URLURL TypeDescription
Lee, Seunghoon0000-0003-3665-587X
Huix-Rotllant, Miquel0000-0002-2131-7328
Filatov, Michael0000-0002-1541-739X
Choi, Cheol Ho0000-0002-8757-1396
Additional Information:© 2021 The Authors. Published by American Chemical Society. Received: March 4, 2021; Accepted: April 28, 2021; Published: April 30, 2021. This work was supported by the Samsung Science and Technology Foundations (SSTF-BA1701-12 to C.H.C.) for the fundamental theory developments and the NRF funded by the Ministry of Science and ICT (2019H1D3A2A02102948 to M.F., 2019K1A3A1A21031668, 2020R1A2C2008246 and 2020R1A5A1019141 to C.H.C.) for the applications of developed theories. The authors declare no competing financial interest.
Funding AgencyGrant Number
Samsung Science and Technology FoundationSSTF-BA1701-12
National Research Foundation of Korea2019H1D3A2A02102948
National Research Foundation of Korea2019K1A3A1A21031668
National Research Foundation of Korea2020R1A2C2008246
National Research Foundation of Korea2020R1A5A1019141
Subject Keywords:Cytosine, Mathematical methods, Electron correlation, Computational chemistry, Thymine
Issue or Number:18
Record Number:CaltechAUTHORS:20210507-134243476
Persistent URL:
Official Citation:Impact of the Dynamic Electron Correlation on the Unusually Long Excited-State Lifetime of Thymine. Woojin Park, Seunghoon Lee, Miquel Huix-Rotllant, Michael Filatov, and Cheol Ho Choi. The Journal of Physical Chemistry Letters 2021 12 (18), 4339-4346; DOI: 10.1021/acs.jpclett.1c00712
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:109012
Deposited By: Tony Diaz
Deposited On:07 May 2021 21:05
Last Modified:17 May 2021 16:53

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