Why Density Functionals Should Not Be Judged Primarily by Atomization Energies

John P. Perdew, Jianwei Sun, Adrienn Ruzsinszky, Pál D. Mezei, Gábor István Csonka
2016 Periodica Polytechnica: Chemical Engineering  
While most molecules and solids are spin-unpolarized, most chemically-active atoms are partly spin-polarized. As a result, the errors of the spin-dependence of a density functional are much more troublesome for atomization energies than they are for typical reaction or formation energies. This observation explains why the atomization energy errors of approximate functionals do not correlate with their other errors, and why the errors of atomization energies for a given functional can be
more » ... onal can be radically reduced by fitting the energies of the atoms. We present an illustrative example from the recent nonempirical construction of the SCAN meta-generalized gradient approximation.
doi:10.3311/ppch.8356 fatcat:mll4twpr3ffwhn662kzi4m2mli