field-perturbed density has enough overlap with the CAP. Contrasting this behavior is the spectrum computed using r 0 = 18.5 bohr (Fig. ), which exhibits fictitious peaks at precisely the same energies, albeit very narrow ones, and well-defined features in the HHG spectrum are still obtained at energies well above these ionization channels and well above the predicted cutoff energy. According to Table , there are a total of 23 basis functions whose HWHM exceeds 9.5 bohr, and 14 basis functions where the HWHM is greater than 18.5 bohr. We conclude that r 0 = 18.5 bohr does not have good overlap with the atom-centered basis functions and the nonzero regions of the CAP reside largely outside of the region that has basis function support.