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Title: Solvent effects on the ultrafast nonradiative deactivation mechanisms of thymine in aqueous solution: Excited-state QM/MM molecular dynamics simulations

Abstract

On-the-fly excited-state quantum mechanics/molecular mechanics molecular dynamics (QM/MM-MD) simulations of thymine in aqueous solution are performed to investigate the role of solvent water molecules on the nonradiative deactivation process. The complete active space second-order perturbation theory (CASPT2) method is employed for a thymine molecule as the QM part in order to provide a reliable description of the excited-state potential energies. It is found that, in addition to the previously reported deactivation pathway involving the twisting of the C-C double bond in the pyrimidine ring, another efficient deactivation pathway leading to conical intersections that accompanies the out-of-plane displacement of the carbonyl group is observed in aqueous solution. Decay through this pathway is not observed in the gas phase simulations, and our analysis indicates that the hydrogen bonds with solvent water molecules play a key role in stabilizing the potential energies of thymine in this additional decay pathway.

Authors:
; ; ;  [1]
  1. Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan)
Publication Date:
OSTI Identifier:
22251310
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 139; Journal Issue: 21; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; AQUEOUS SOLUTIONS; DEACTIVATION; EXCITED STATES; MOLECULAR DYNAMICS METHOD; PERTURBATION THEORY; POTENTIAL ENERGY; QUANTUM MECHANICS; SIMULATION; SOLVENTS; THYMINE; WATER

Citation Formats

Nakayama, Akira, Arai, Gaku, Yamazaki, Shohei, and Taketsugu, Tetsuya. Solvent effects on the ultrafast nonradiative deactivation mechanisms of thymine in aqueous solution: Excited-state QM/MM molecular dynamics simulations. United States: N. p., 2013. Web. doi:10.1063/1.4833563.
Nakayama, Akira, Arai, Gaku, Yamazaki, Shohei, & Taketsugu, Tetsuya. Solvent effects on the ultrafast nonradiative deactivation mechanisms of thymine in aqueous solution: Excited-state QM/MM molecular dynamics simulations. United States. https://doi.org/10.1063/1.4833563
Nakayama, Akira, Arai, Gaku, Yamazaki, Shohei, and Taketsugu, Tetsuya. 2013. "Solvent effects on the ultrafast nonradiative deactivation mechanisms of thymine in aqueous solution: Excited-state QM/MM molecular dynamics simulations". United States. https://doi.org/10.1063/1.4833563.
@article{osti_22251310,
title = {Solvent effects on the ultrafast nonradiative deactivation mechanisms of thymine in aqueous solution: Excited-state QM/MM molecular dynamics simulations},
author = {Nakayama, Akira and Arai, Gaku and Yamazaki, Shohei and Taketsugu, Tetsuya},
abstractNote = {On-the-fly excited-state quantum mechanics/molecular mechanics molecular dynamics (QM/MM-MD) simulations of thymine in aqueous solution are performed to investigate the role of solvent water molecules on the nonradiative deactivation process. The complete active space second-order perturbation theory (CASPT2) method is employed for a thymine molecule as the QM part in order to provide a reliable description of the excited-state potential energies. It is found that, in addition to the previously reported deactivation pathway involving the twisting of the C-C double bond in the pyrimidine ring, another efficient deactivation pathway leading to conical intersections that accompanies the out-of-plane displacement of the carbonyl group is observed in aqueous solution. Decay through this pathway is not observed in the gas phase simulations, and our analysis indicates that the hydrogen bonds with solvent water molecules play a key role in stabilizing the potential energies of thymine in this additional decay pathway.},
doi = {10.1063/1.4833563},
url = {https://www.osti.gov/biblio/22251310}, journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 21,
volume = 139,
place = {United States},
year = {Sat Dec 07 00:00:00 EST 2013},
month = {Sat Dec 07 00:00:00 EST 2013}
}