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Updated: Mar 7, 2026

Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method
Published on: July 19, 2019
Fast and slow excited-state intramolecular proton transfer in 3-hydroxychromone: a two-state story?
Aurelie Perveaux1, Maxime Lorphelin2, Benjamin Lasorne3
1Laboratoire de Chimie Physique (UMR 8000), CNRS, Université Paris-Sud, F-91405 Orsay, France. perveaux@tugraz.at and Institut Charles Gerhardt (UMR 5253), CNRS, Université de Montpellier, F-34095 Montpellier, France.
Abstract:
The photodynamics of 3-hydroxychromone in its first-excited singlet electronic state (bright state of ππ* character) is investigated with special emphasis given to two types of reaction pathways: the excited-state intramolecular-proton-transfer coordinate and the hydrogen-torsion coordinate linking the excited cis and trans isomers. A newly-found conical intersection with the second-excited singlet electronic state (dark state of nπ* character) is suspected to be, to some extent, the reason for the slower rate constant. This hypothesis based on quantum-chemistry calculations is supported by quantum-dynamics simulations in full dimensionality. They show significant transfer of electronic population and provide consistently a vibronic interpretation for the forbidden band in the UV absorption spectrum.
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