Thus, while the proposal of an alternative gas-phase correction scheme is outside the scope of this work, we do think that the existing O 2 correction scheme does introduce a source of variability associated with the chosen functional. For hybrid functionals, this variability should be small in most cases, but perhaps not insignificant in light of the otherwise high accuracy of these functionals. Improved corrections may therefore be necessary to match the high performance of modern functionals without introducing spurious errors.