Accurate and Numerically Efficient r²SCAN Meta-Generalized Gradient Approximation

The recently proposed rSCAN functional [ <i>J. Chem. Phys.</i> 2019 150, 161101] is a regularized form of the SCAN functional [ <i>Phys. Rev. Lett.</i> 2015 115, 036402] that improves SCAN's numerical performance at the expense of breaking constraints known from the exact exchange-correlation functional. We construct a new meta-generalized gradient approximation by restoring exact constraint adherence to rSCAN. The resulting functional maintains rSCAN's numerical performance while restoring the transferable accuracy of SCAN.