## 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(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.

- Authors:

- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA

- Publication Date:

- Research Org.:
- Univ. of Illinois at Urbana-Champaign, IL (United States)

- Sponsoring Org.:
- USDOE Office of Science (SC)

- OSTI Identifier:
- 1535305

- Grant/Contract Number:
- SC0008692

- Resource Type:
- Accepted Manuscript

- Journal Name:
- Journal of Chemical Physics

- Additional Journal Information:
- Journal Volume: 146; Journal Issue: 12; Journal ID: ISSN 0021-9606

- Publisher:
- American Institute of Physics (AIP)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- Chemistry; Physics

### Citation Formats

```
Krongchon, Kittithat, Busemeyer, Brian, and Wagner, Lucas K. Accurate barrier heights using diffusion Monte Carlo. United States: N. p., 2017.
Web. doi:10.1063/1.4979059.
```

```
Krongchon, Kittithat, Busemeyer, Brian, & Wagner, Lucas K. Accurate barrier heights using diffusion Monte Carlo. United States. doi:10.1063/1.4979059.
```

```
Krongchon, Kittithat, Busemeyer, Brian, and Wagner, Lucas K. Tue .
"Accurate barrier heights using diffusion Monte Carlo". United States. doi:10.1063/1.4979059. https://www.osti.gov/servlets/purl/1535305.
```

```
@article{osti_1535305,
```

title = {Accurate barrier heights using diffusion Monte Carlo},

author = {Krongchon, Kittithat and Busemeyer, Brian and Wagner, Lucas K.},

abstractNote = {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.},

doi = {10.1063/1.4979059},

journal = {Journal of Chemical Physics},

number = 12,

volume = 146,

place = {United States},

year = {2017},

month = {3}

}

*Citation information provided by*

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Web of Science

Works referenced in this record:

##
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journal, October 1996

- Perdew, John P.; Burke, Kieron; Ernzerhof, Matthias
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