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Published on: July 19, 2019
Nonadiabatic excited-state intramolecular proton transfer in 3-hydroxyflavone: S2 state involvement via multi-mode
Neethu Anand1, Kai Welke2, Stephan Irle3
1Indian Institute of Science Education and Research, Thiruvananthapuram, Maruthamala PO,Vithura, Thiruvananthapuram 695551, India.
Abstract:
The excited-state intramolecular proton transfer process in 3-hydroxyflavone is investigated based on the computed structural parameters and energetics of stationary points of vibronically coupled S1-S2 potential energy surfaces. A conical intersection close to the Franck-Condon point on S1 is identified. The minimum energy of the conical intersection is found to be near-degenerate with the equilibrium minimum of S2. Quantum nuclear wavepacket simulations revealed a small population transfer from the "bright" S1 to "dark" S2 on a time scale shorter than the O-H stretching vibrational period. Such a nonadiabatic transition opens up the possibility of new photophysical and photochemical pathways, including the proton transfer via S2.
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