Beyond the Born-Oppenheimer approximation with quantum Monte Carlo methods

Norm M. Tubman, Ilkka Kylänpää, Sharon Hammes-Schiffer, David M. Ceperley

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

In this work we develop tools that enable the study of nonadiabatic effects with variational and diffusion Monte Carlo methods. We introduce a highly accurate wave-function ansatz for electron-ion systems that can involve a combination of both clamped ions and quantum nuclei. We explicitly calculate the ground-state energies of H2, LiH, H2O, and FHF- using fixed-node quantum Monte Carlo with wave-function nodes that explicitly depend on the ion positions. The obtained energies implicitly include the effects arising from quantum nuclei and electron-nucleus coupling. We compare our results to the best theoretical and experimental results available and find excellent agreement.

Original languageEnglish (US)
Article number042507
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Volume90
Issue number4
DOIs
StatePublished - Oct 21 2014
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics

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