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Charge transfer excitations from exact and approximate ensemble Kohn-Sham theory.

Timothy GouldLeeor KronikStefano Pittalis
Published in: The Journal of chemical physics (2018)
By studying the lowest excitations of an exactly solvable one-dimensional soft-Coulomb molecular model, we show that components of Kohn-Sham ensembles can be used to describe charge transfer processes. Furthermore, we compute the approximate excitation energies obtained by using the exact ensemble densities in the recently formulated ensemble Hartree-exchange theory [T. Gould and S. Pittalis, Phys. Rev. Lett. 119, 243001 (2017)]. Remarkably, our results show that triplet excitations are accurately reproduced across a dissociation curve in all cases tested, even in systems where ground state energies are poor due to strong static correlations. Singlet excitations exhibit larger deviations from exact results but are still reproduced semi-quantitatively.
Keyphrases
  • density functional theory
  • molecular dynamics
  • convolutional neural network
  • energy transfer
  • neural network
  • double blind
  • clinical trial
  • deep learning
  • machine learning
  • quantum dots
  • electron transfer