# Effective non-adiabatic Hamiltonians for the quantum nuclear motion over coupled electronic states.

@article{Mtyus2019EffectiveNH,
title={Effective non-adiabatic Hamiltonians for the quantum nuclear motion over coupled electronic states.},
author={Edit M{\'a}tyus and Stefan Teufel},
journal={The Journal of chemical physics},
year={2019},
volume={151 1},
pages={
014113
}
}
• Published 29 March 2019
• Physics
• The Journal of chemical physics
The quantum mechanical motion of the atomic nuclei is considered over a single- or a multidimensional subspace of electronic states which is separated by a gap from the rest of the electronic spectrum over the relevant range of nuclear configurations. The electron-nucleus Hamiltonian is block-diagonalized up to O(εn+1) through a unitary transformation of the electronic subspace, and the corresponding nth-order effective Hamiltonian is derived for the quantum nuclear motion. Explicit but general…

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