An assessment of numerical behaviors of the r²SCAN exchange-correlation functional

The meta-GGA exchange-correlation functional, r²SCAN, [1] has received considerable attention. Accessments of its use in generalized density functional simulations of a variety of materials report typically improved agreement with experimental measurements compared with other functionals (Ref. [2], for example). However, numerical challenges due to the functional form of r²SCAN have also been reported [3,4], which perhaps has slowed its incorporation into several of the public-domain electronic structure codes. We report a systematic study of some of the numerical issues associated with using the r²SCAN exchange-correlation functional within generalized density functional computations.

1. J. W. Furness, et al., J. Phys. Chem. Lett. 11, 8208 (2020).

2. M. Kothakonda, et al., ACS Mater. Au 3, 102 (2023).

3. N. A. W. Holzwarth, M. Torrent, et al., Phys. Rev. Mat. 105, 125124 (2022).

4. S. Lehtola, J.Chem. Theory Comput. 19, 2502 (2023).