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Title: Quantum-mechanical approach to predissociation of water dimers in the vibrational adiabatic representation: Importance of channel interactions

The results of application of the quantum-mechanical adiabatic theory to vibrational predissociation (VPD) of water dimers, (H{sub 2}O){sub 2} and (D{sub 2}O){sub 2}, are presented. We consider the VPD processes including the totally symmetric OH mode of the dimer and the bending mode of the fragment. The VPD in the adiabatic representation is induced by breakdown of the vibrational adiabatic approximation, and two types of nonadiabatic coupling matrix elements are involved: one provides the VPD induced by the low-frequency dissociation mode and the other provides the VPD through channel interactions induced by the low-frequency modes. The VPD rate constants were calculated using the Fermi golden rule expression. A closed form for the nonadiabatic transition matrix element between the discrete and continuum states was derived in the Morse potential model. All of the parameters used were obtained from the potential surfaces of the water dimers, which were calculated by the density functional theory procedures. The VPD rate constants for the two processes were calculated in the non-Condon scheme beyond the so-called Condon approximation. The channel interactions in and between the initial and final states were taken into account, and those are found to increase the VPD rates by 3(1) orders ofmore » magnitude for the VPD processes in (H{sub 2}O){sub 2} ((D{sub 2}O){sub 2}). The fraction of the bending-excited donor fragments is larger than that of the bending-excited acceptor fragments. The results obtained by quantum-mechanical approach are compared with both experimental and quasi-classical trajectory calculation results.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [3] ;  [4]
  1. Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China)
  2. Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)
  3. Department of Applied Chemistry, Institute of Molecular Science and Center for Interdisciplinary Molecular Science, National Chiao-Tung University, Shin-Chu 300, Taiwan (China)
  4. (Japan)
Publication Date:
OSTI Identifier:
22493575
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 143; Journal Issue: 8; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ADIABATIC APPROXIMATION; COMPARATIVE EVALUATIONS; COUPLING; DENSITY FUNCTIONAL METHOD; DIMERS; HEAVY WATER; MATRIX ELEMENTS; MORSE POTENTIAL; PREDISSOCIATION; QUANTUM MECHANICS; REACTION KINETICS; SURFACES; SYMMETRY