Accurate barrier heights using diffusion Monte Carlo

Kittithat Krongchon, Brian Busemeyer, Lucas K. Wagner

Research output: Contribution to journalArticlepeer-review

Abstract

Fixed node diffusion Monte Carlo (DMC) has been performed on a test set of forward and reverse barrier heights for 19 non-hydrogen-transfer reactions, and the nodal error has been assessed. The DMC results are robust to changes in the nodal surface, as assessed by using different mean-field techniques to generate single determinant wave functions. Using these single determinant nodal surfaces, DMC results in errors of 1.5(1) kcal/mol on barrier heights. Using the large data set of DMC energies, we attempted to find good descriptors of the fixed node error. It does not correlate with a number of descriptors including change in density but does show some correlation with the gap between the highest occupied and lowest unoccupied orbital energies in the mean-field calculation.

Original languageEnglish (US)
Article number124129
JournalJournal of Chemical Physics
Volume146
Issue number12
DOIs
StatePublished - Mar 28 2017

ASJC Scopus subject areas

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

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