Unified description of hydrogen bonding and of proton transfer by a two-state effective Hamiltonian

Abstract

An effective Hamiltonian is considered for hydrogen bonding between two molecules due to the quantum mechanical interaction between the orbitals of the H-atom and the donor and acceptor atoms in the molecules. The Hamiltonian acts on two diabatic states and has a simple chemically motivated form for its matrix elements. The model gives insight into the "H-bond puzzle", describes different classes of bonds, and empirical correlations between the donor-acceptor distance R and binding energies, bond lengths, and the softening of vibrational frequencies. A key prediction is the UV photo-dissociation of H-bonded complexes via an excited electronic state with an exalted vibrational frequency.

5 pages, 7 figures, minor changes

References in corpus (2)

• Quantum entanglement between electronic and vibrational degrees of freedom in molecules
• A Diabatic Three-State Representation of Photoisomerization in the Green Fluorescent Protein Chromophore

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