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Photodissociation of phenol in the adiabatic representation: Tunneling, motions of phenyl ring, and kinetic isotope effects
Author(s) -
He Ying,
Zhao Huali,
Wang Wenji
Publication year - 2018
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.25786
Subject(s) - chemistry , dissociation (chemistry) , photodissociation , excited state , kinetic isotope effect , potential energy , arrhenius plot , photochemistry , kinetic energy , activation energy , arrhenius equation , quantum yield , quantum tunnelling , atomic physics , physics , quantum mechanics , deuterium , fluorescence
The photodissociation of phenol is a prototype of the photoinduced hydrogen detachment reaction. The dissociation rates of phenol through the excited S 1 state are calculated with the quantum instanton method in full dimensionality. The Arrhenius plot of the rates shows that the quantum tunneling dominates the OH bond dissociation at low temperatures. The degrees of freedom of phenyl ring (C 6 H 5 ) play extremely important roles in the dissociation of phenol. Fixing the phenyl ring at the equilibrium geometry can only provide reliable rates between 400 K and 800 K. The motions of phenyl ring have an impact on enhancing the dissociation by lowering the free energy barrier. The larger the amplitudes of the phenyl ring motions are, the more the free energy barrier will be reduced. The dissociation rates of C 6 H 5 OH are much larger than those of C 6 H 5 OD, which is due to the zero‐point energy and entropy effects.