  We review the theoretical background for obtaining both quantum defects and
scattering phase shifts from time-dependent density functional theory. The
quantum defect on the negative energy side of the spectrum and the phase shift
on the positive energy side merge continuously at E=0, allowing both to be
found by the same method. We illustrate with simple one-dimensional examples:
the spherical well and the delta well potential. As an example of a real
system, we study in detail elastic electron scattering from the He${}^{+}$ ion.
We show how the results are influenced by different approximations to the
unknown components in (time-dependent) density functional theory: the ground
state exchange-correlation potential and time-dependent kernel. We also revisit
our previously obtained results for $e$-H scattering. Our results are
remarkably accurate in may cases, but fail qualitatively in others.
