Previous work, along with the electron-affinity methods discussed here, has established that the pre-edge and main-edge features may only be accurately captured if variational orbital relaxation is encoded into the wave function. However, it was also suggested that a lack of double excitations (primarily functioning as a source of orbital relaxation) was also to blame for the failure of TP-DFT to capture the long post-edge tail exhibited by NH 3 and NH + 4 . We investigate the origin of the post-edge tail in NH 3 and NH + 4 by replicating the size of the explicit quantum mechanical solvent subsystem (four coordinating water molecules) from Ref. 22 and computing the full spectrum using EA-TDDFT.