# Parameters and Convergence

## Calculation Parameters

We use the projector-augmented wave (PAW) or modeling core electrons with an energy cutoff of 680 eV. K-point grids were generated automatically by VASP using KSPACING values ranging from 0.22/Å to 0.44/Å. Specifically, the Monkhorst-Pack method is used for grid generation (with $$\Gamma$$-centered for hexagonal cells), and the tetrahedron method is used to perform the k-point integrations. These were determined from the GGA-estimated bandgap of each material based on the work by Wisesa et al. [\[1\]](#references). More details regarding the calculation method can be found in ref [\[2\]](#references); however, the Materials Project has updated many parameters as documented throughout the Methodology sections. The most up-to-date input sets can be [found here](https://github.com/materialsproject/pymatgen/blob/f9d9fe8e0ce09ef30cc03bcc4e9937d27afd5a6a/src/pymatgen/io/vasp/sets.py#L1315).

### Convergence

Plane-wave energy cutoff and k-point density settings were selected such that formation energies converged within approximately 1 meV/atom for a benchmark set of 21 materials and were selected to be conservatively high [\[2\]](#references):

| Formula  | Spacegroup | Materials Project ID |
| -------- | ---------- | -------------------- |
| AlN      | P63mc      | mp-661               |
| Al2O3    | R3c        | mp-1143              |
| BN       | P63/mmc    | mp-984               |
| BaBeSiO4 | Cm         | mp-550751            |
| CeO2     | Fm3m       | mp-20194             |
| CaF2     | Fm3m       | mp-2741              |
| EuO      | Fm3m       | mp-21394             |
| FeP      | Pnma       | mp-1005              |
| FeS      | P4/nmm     | mp-505531            |
| GaAs     | F43m       | mp-2534              |
| InSb     | F43m       | mp-20012             |
| LiH      | Fm3m       | mp-23703             |
| LiF      | Fm3m       | mp-1138              |
| LiCl     | P63mc      | mp-1185319           |
| Li2O     | Fm3m       | mp-1960              |
| LiN      | I4m2       | mp-1059612           |
| MoS2     | P3m1       | mp-1027525           |
| NaI      | Fm3m       | mp-23268             |
| SrI2     | Pnma       | mp-568284            |
| TiO2     | C2/m       | mp-554278            |
| VO2      | P21/c      | mp-1102963           |

## References

\[1] P. Wisesa, K. A. McGill, and T. Mueller, Efficient generation of generalized Monkhorst-Pack grids through the use of informatics, Phys. Rev. B 93, 1 (2016).

\[2] R. Kingsbury, A. S. Gupta, C. J. Bartel, J. M. Munro, S. Dwaraknath, M. Horton, and K. A. Persson Phys. Rev. Materials 6, 013801 (2022)


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.materialsproject.org/methodology/materials-methodology/calculation-details/r2scan-calculations/parameters-and-convergence.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.