Assessing the effect of regularization on the molecular properties predicted by SCAN and self-interaction corrected SCAN meta-GGA

Recent regularization of the SCAN meta-GGA functional (rSCAN) has simplified the numerical complexities of the SCAN functional, alleviating SCAN's stringent demand on the numerical integration grids to some extent. The regularization of rSCAN, however, results in the breaking of some constraint...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2020-08, Vol.22 (32), p.186-187
Main Authors: Yamamoto, Yoh, Salcedo, Alan, Diaz, Carlos M, Alam, Md Shamsul, Baruah, Tunna, Zope, Rajendra R
Format: Article
Language:English
Subjects:
Atomizing
Dipole moments
Electron gas
Electrons
Ionization potentials
Magnetic properties
Magnets
Molecular properties
Numerical integration
Raman spectra
Regularization
Test sets
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Summary:Recent regularization of the SCAN meta-GGA functional (rSCAN) has simplified the numerical complexities of the SCAN functional, alleviating SCAN's stringent demand on the numerical integration grids to some extent. The regularization of rSCAN, however, results in the breaking of some constraints such as the uniform electron gas limit, the slowly varying density limit, and coordinate scaling of the iso-orbital indicator. Here, we assess the effects of regularization on the electronic, structural, vibrational, and magnetic properties of molecules by comparing the SCAN and rSCAN predictions. The properties studied include atomic energies, atomization energies, ionization potentials, electron affinities, barrier heights, infrared intensities, dissociation and reaction energies, spin moments of molecular magnets, and isomer ordering of water clusters. Our results show that rSCAN requires less dense numerical grids and gives very similar results to those of SCAN for all properties examined with the exception of atomization energies, which are worsened in rSCAN. We also examine the performance of self-interaction-corrected (SIC) rSCAN with respect to SIC-SCAN using the Perdew-Zunger (PZ) SIC method. The PZSIC method uses orbital densities to compute one-electron self-interaction errors and places an even more stringent demand on numerical grids. Our results show that SIC-rSCAN gives marginally better performance than SIC-SCAN for almost all properties studied in this work with numerical grids that are on average half or less as dense as that needed for SIC-SCAN. Regularized SCAN (rSCAN) gives molecular properties similar to SCAN except for atomization energies. After the removal of self-interaction errors, rSCAN describes properties slightly better than the self-interaction corrected SCAN.
ISSN:1463-9076
1463-9084
DOI:10.1039/d0cp02717k