Accurate barrier heights using diffusion Monte Carlo

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(5) 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 correlate with the gap between the highest occupied and lowest unoccupied orbital energies in the mean-field calculation.

6 pages, 4 figures, 1 table

References in corpus (3)

• Applications of quantum Monte Carlo methods in condensed systems
• Energies of the first row atoms from quantum Monte Carlo
• Energetics and Dipole Moment of Transition Metal Monoxides by Quantum Monte Carlo

Cited by in corpus (4)

• Towards DMC accuracy across chemical space with scalable $\Delta$-QML
• Fractional charge by fixed-node diffusion Monte Carlo
• Reproducibility of fixed-node diffusion Monte Carlo across diverse community codes: The case of water-methane dimer
• An efficient hybrid orbital representation for quantum Monte Carlo calculations