How large are nonadiabatic effects in atomic and diatomic systems?

Yubo Yang, Ilkka Kylänpää, Norm M. Tubman, Jaron T. Krogel, Sharon Hammes-Schiffer, David M. Ceperley

Research output: Contribution to journalArticle

Abstract

With recent developments in simulating nonadiabatic systems to high accuracy, it has become possible to determine how much energy is attributed to nuclear quantum effects beyond zero-point energy. In this work, we calculate the non-relativistic ground-state energies of atomic and molecular systems without the Born-Oppenheimer approximation. For this purpose, we utilize the fixed-node diffusion Monte Carlo method, in which the nodes depend on both the electronic and ionic positions. We report ground-state energies for all systems studied, ionization energies for the first-row atoms and atomization energies for the first-row hydrides. We find the ionization energies of the atoms to be nearly independent of the Born-Oppenheimer approximation, within the accuracy of our results. The atomization energies of molecular systems, however, show small effects of the nonadiabatic coupling between electrons and nuclei.

Original languageEnglish (US)
Article number124308
JournalJournal of Chemical Physics
Volume143
Issue number12
DOIs
StatePublished - Sep 28 2015

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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    Yang, Y., Kylänpää, I., Tubman, N. M., Krogel, J. T., Hammes-Schiffer, S., & Ceperley, D. M. (2015). How large are nonadiabatic effects in atomic and diatomic systems? Journal of Chemical Physics, 143(12), [124308]. https://doi.org/10.1063/1.4931667