Eur. Phys. J. D 19, 293-305 (2002)
https://doi.org/10.1140/epjd/e20020082

Quantum chemical construction of a reduced reaction Hamiltonian and T₁-relaxation and pure T₂-dephasing rates for the proton transfer in 3-chlorotropolone

¹ Open Laboratory of Bond-Selective Chemistry, University of Science and Technology of China, Hefei, China and Department of Chemistry, Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, P.R. China
² Institut für Chemie, Physikalische und Theoretische Chemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany

Corresponding author: ^a rxxu@mail.ustc.edu.cn

Received: 19 November 2001
Revised: 19 February 2002
Published online: 15 June 2002

Abstract

Separating multidimensional problems into that of a relevant system which is coupled to a bath of harmonic oscillators is a common concept in condensed phase theory. Focusing on the specific problem of intramolecular proton transfer in an isolated tropolone derivative, we consider the reactive proton moving in the plane of the molecule as the system and the remaining substrate normal modes as the bath. An all-Cartesian system-plus-substrate Hamiltonian is constructed employing density functional theory. It is then used to determine the temperature-dependent effective reduced reaction Hamiltonian and the state-to-state dissipation rates induced via the system-substrate coupling up to the bi-quadratic order. The important substrate modes for the T₁-relaxation and the pure T₂-dephasing rates, which are either intra- or inter-well in nature, are identified numerically and analyzed physically with molecular details.