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Download fileMatrix Product State Formulation of the MCTDH Theory in Local Mode Representations for Anharmonic Potentials
journal contribution
posted on 2022-05-24, 04:03 authored by Kentaro Hino, Yuki KurashigeThe
matrix product state formulation of the multiconfiguration
time-dependent Hartree theory, MPS-MCTDH, reported previously [Kurashige, J. Chem. Phys. 2018, 19, 194114]
is extended to realistic anharmonic potentials with n-mode representations beyond the linear vibronic coupling model.
For realistic vibrational potentials, the local mode representation
should give a more compact representation of the potentials, i.e.,
lowering the dimensionality of the entanglements, than the normal
coordinates, and the MPS-MCTDH formulation should work more efficiently
and maintain the accuracy with a small bond dimension of the MPS ansatz.
In fact, it was confirmed that the use of the local coordinates made
the interaction matrices diagonal dominant and the number of terms
in the n-body expansion of the potentials was significantly
reduced. The method was applied to the IR spectrum of the CH2O molecule, the zero-point energies, and the vibrational energy redistribution
dynamics of polyenes C2nH2n+2. The results showed that the efficiency of the
MPS-MCTDH method is significantly accelerated by the use of local
coordinates even if the long-range interactions are included in the
potential.
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small bond dimensionlocal mode representationse ., lowering>- body expansionlocal coordinates madelocal coordinates evenlocal mode representationdependent hartree theoryrealistic vibrational potentialsrealistic anharmonic potentials2 subanharmonic potentialsnormal coordinatescompact representationn 19 mctdh theorysignificantly reducedsignificantly acceleratedresults showedreported previouslyrange interactionspolyenes cpoint energiesphys .multiconfiguration timeir spectrum> sub>, 194114