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

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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.

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Details 詳細情報について

  • CRID
    1050282813992311168
  • NII Article ID
    120005385310
  • NII Book ID
    AA00694991
  • HANDLE
    2115/54756
  • ISSN
    00219606
  • Text Lang
    en
  • Article Type
    journal article
  • Data Source
    • IRDB
    • CiNii Articles

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