Here, E κ is the actual field amplitude in the sense of Eq. ( ) but that quantity is not needed to compute the absorption spectrum S(ω). The perturbing field consists of equal components in each Cartesian direction ( Ēx = Ēy = Ēz ), which ensures that the perturbation creates a superposition of all excited states regardless of electronic symmetry. We set Ēκ = 10 -4 a.u. for all calculations reported here. Integral screening and shell-pair drop tolerances are set to 10 -12 a.u.. Some basis-set testing is presented in Section 3 B. These tests, and many of the spectra presented in Section 4, are computed using "short-range corrected" (SRC) density functionals known as SRC1 or SRC2. These are range-separated hybrid functionals based on the short-range exchange functional µBLYP, parameterized specifically for LR-TDDFT calculations at elemental K-edges. These functionals use a large fraction of exact exchange that is attenuated on a length scale of < 1 Å, which presumably corrects for differential self-interaction error between the core and valence virtual orbitals. Actually there are two versions of both functionals, SRCn-r1 and SRCn-r2, where the former are parameterized for "first-row" elements (C, N, O, etc.) and contains 50% (SRC1) or 55% (SRC2) short-range Hartree-Fock exchange, whereas the "second-row" versions (SRCn-r2) contain 87% (SRC1) and 91% (SRC2) short-range Hartree-Fock exchange. The SG-1 numerical quadrature grid is used to integrate the exchangecorrelation functional.