# Quantitative estimation of localization errors of 3d transition metal pseudopotentials in diffusion Monte Carlo

## Abstract

The necessarily approximate evaluation of non-local pseudopotentials in diffusion Monte Carlo (DMC) introduces localization errors. In this paper, we estimate these errors for two families of non-local pseudopotentials for the first-row transition metal atoms Sc–Zn using an extrapolation scheme and multideterminant wavefunctions. Sensitivities of the error in the DMC energies to the Jastrow factor are used to estimate the quality of two sets of pseudopotentials with respect to locality error reduction. The locality approximation and T-moves scheme are also compared for accuracy of total energies. After estimating the removal of the locality and T-moves errors, we present the range of fixed-node energies between a single determinant description and a full valence multideterminant complete active space expansion. The results for these pseudopotentials agree with previous findings that the locality approximation is less sensitive to changes in the Jastrow than T-moves yielding more accurate total energies, however not necessarily more accurate energy differences. For both the locality approximation and T-moves, we find decreasing Jastrow sensitivity moving left to right across the series Sc–Zn. The recently generated pseudopotentials of Krogel et al. reduce the magnitude of the locality error compared with the pseudopotentials of Burkatzki et al. by an average estimated 40% usingmore »

- Authors:

- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division

- Publication Date:

- Research Org.:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

- Sponsoring Org.:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)

- OSTI Identifier:
- 1376434

- Alternate Identifier(s):
- OSTI ID: 1368604

- Grant/Contract Number:
- AC05-00OR22725

- Resource Type:
- Journal Article: Accepted Manuscript

- Journal Name:
- Journal of Chemical Physics

- Additional Journal Information:
- Journal Volume: 147; Journal Issue: 2; Journal ID: ISSN 0021-9606

- Publisher:
- American Institute of Physics (AIP)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Electronic structure calculations; Metalloids; Monte Carlo methods; Wave functions; Matrix theory

### Citation Formats

```
Dzubak, Allison L., Krogel, Jaron T., and Reboredo, Fernando A..
```*Quantitative estimation of localization errors of 3d transition metal pseudopotentials in diffusion Monte Carlo*. United States: N. p., 2017.
Web. doi:10.1063/1.4991414.

```
Dzubak, Allison L., Krogel, Jaron T., & Reboredo, Fernando A..
```*Quantitative estimation of localization errors of 3d transition metal pseudopotentials in diffusion Monte Carlo*. United States. doi:10.1063/1.4991414.

```
Dzubak, Allison L., Krogel, Jaron T., and Reboredo, Fernando A.. Mon .
"Quantitative estimation of localization errors of 3d transition metal pseudopotentials in diffusion Monte Carlo". United States.
doi:10.1063/1.4991414. https://www.osti.gov/servlets/purl/1376434.
```

```
@article{osti_1376434,
```

title = {Quantitative estimation of localization errors of 3d transition metal pseudopotentials in diffusion Monte Carlo},

author = {Dzubak, Allison L. and Krogel, Jaron T. and Reboredo, Fernando A.},

abstractNote = {The necessarily approximate evaluation of non-local pseudopotentials in diffusion Monte Carlo (DMC) introduces localization errors. In this paper, we estimate these errors for two families of non-local pseudopotentials for the first-row transition metal atoms Sc–Zn using an extrapolation scheme and multideterminant wavefunctions. Sensitivities of the error in the DMC energies to the Jastrow factor are used to estimate the quality of two sets of pseudopotentials with respect to locality error reduction. The locality approximation and T-moves scheme are also compared for accuracy of total energies. After estimating the removal of the locality and T-moves errors, we present the range of fixed-node energies between a single determinant description and a full valence multideterminant complete active space expansion. The results for these pseudopotentials agree with previous findings that the locality approximation is less sensitive to changes in the Jastrow than T-moves yielding more accurate total energies, however not necessarily more accurate energy differences. For both the locality approximation and T-moves, we find decreasing Jastrow sensitivity moving left to right across the series Sc–Zn. The recently generated pseudopotentials of Krogel et al. reduce the magnitude of the locality error compared with the pseudopotentials of Burkatzki et al. by an average estimated 40% using the locality approximation. The estimated locality error is equivalent for both sets of pseudopotentials when T-moves is used. Finally, for the Sc–Zn atomic series with these pseudopotentials, and using up to three-body Jastrow factors, our results suggest that the fixed-node error is dominant over the locality error when a single determinant is used.},

doi = {10.1063/1.4991414},

journal = {Journal of Chemical Physics},

number = 2,

volume = 147,

place = {United States},

year = {Mon Jul 10 00:00:00 EDT 2017},

month = {Mon Jul 10 00:00:00 EDT 2017}

}

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