This repo is a fork of the FLO-SIC 2020 public release (https://github.com/FLOSIC/PublicRelease_2020) containing files implementing the novel and efficient r2SCAN meta-GGA:
J. W. Furness, A. D. Kaplan, J. Ning, J. P. Perdew, and J. Sun, "Accurate and Numerically Efficient r2SCAN Meta-Generalized Gradient Approximation",
J. Phys. Chem. Lett. 11, 8208-8215 (2020). [DOI: 10.1021/acs.jpclett.0c02405]
https://doi.org/10.1021/acs.jpclett.0c02405.
r2SCAN subroutines written by James Furness (@JFurness1, [email protected]). Licensed CC0 (without any access restrictions).
For further information, please see the metadata in r2scan.f or the public r2SCAN code repository
https://gitlab.com/dhamil/r2scan-subroutines.
Two extant files have been modified:
setdftyp.ftn
subvlxc_libxc.F91
The new keywords are R2SCAN for accessing r2 SCAN, and SDBG, which performs SCAN calculations using the subroutines in r2scan.f.
(Please note that these subroutines permit self consistent calculations with SCAN, rSCAN, r++SCAN, r2SCAN and r4SCAN via modification of integer flags therein.)
SDBG can be used to validate the implementation of the subroutines, as has been done in the R2SCAN_tests directory. scan_comps_AE6.xslx compares the existing implementation of SCAN in FLO-SIC with SDBG, and shows agreement is essentially exact.
It appears that Mesh size 1 (intermediate size, intended for rSCAN) can be used with r2SCAN. See the tests in r2scan-test-N-Ne-apr12.xlsx for the atoms N, Ne, and the AE6 set.
R2SCAN_tests/NaCl_dissociation contains a mesh test of the dissociation of NaCl. This again confirms that Mesh 1 can be used for small atoms with r2SCAN.
A few auxiliary files are included in R2SCAN_tests: test_atoms.py and cbs_extrap.py.
These are PySCF scripts used to generate reference exchange-only and exchange-correlation total energies with PySCF.
These reference energies can then be compared against FLO-SIC, as is done in
R2SCAN_tests/atom_tests/atom_calcs_cart_sp_norm_w_cbs.xlsx.
Agreement is generally to 1e-6 Hartree or better.