State-specific approaches to XAS such as orbital-optimized DFT perform that relaxation explicitly, and with spin adaptation, have been demonstrated to work very well. Alternatively, a good approximation is to use the orbitals of the core ion and then reattach the electron, as is done in the static-exchange approximation (STEX) or electron-affinity CIS (EA-CIS). Orbitals of the core-ion reference can be further improved by the inclusion of DFT correlation; a feat accomplished by our group's recently proposed electron-affinity TDDFT (EA-TDDFT) approach. None of these approaches explicitly include double (or higher-order) excitations, but because they use site-specific orbital-optimized references more of the correlation energy is recovered in accordance with E * c (0) -E * c (opt) > 0. In this sense, these methods can be considered to recover "implicit" or "mean-field" correlation effects, whereas methods that use the n-electron ground state reference require "explicit" correlation supplied by direct inclusion of ancillary excitations. Herein, we will explore the importance of implicit correlation as it pertains to solution-phase XAS calculations by choosing the core-ionized orbitals as the initial reference for linear-response theories that incorporate only single excitations into the final wave function.