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Quantum Dynamics Study of the Excited‐State Double‐Proton Transfer in 2,2′‐Bipyridyl‐3,3′‐diol
Author(s) -
Gelabert Ricard,
Moreno Miquel,
Lluch José M.
Publication year - 2004
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200400078
Subject(s) - excited state , diol , dynamics (music) , proton , chemistry , quantum , state (computer science) , computational chemistry , photochemistry , atomic physics , physics , quantum mechanics , organic chemistry , computer science , algorithm , acoustics
Abstract Density functional theory and quantum dynamics simulations have been used to study the double‐proton transfer reaction in 2,2′‐bipyridyl‐3,3′‐diol in the first singlet excited electronic state. This process is experimentally known to be branched: It consists of a fast, concerted reaction mechanism (τ≈100 fs) and a stepwise reaction mechanism [with a fast initial step (τ≈100 fs) and a slower final step (τ≈10 ps)]. Quantum dynamics simulations on a two‐dimensional model reveal that the concerted reaction occurs despite the nonexistence of a concerted reaction path, but they fail to explain the relative slowness of the stepwise mechanism. A qualitative simulation using a three‐dimensional model suggests that internal vibrational relaxation (IVR) might be the reason why the second stage of the stepwise mechanism is so slow.