title: Time-dependent density functional theory of high excitations: to infinity, and beyond.
abstract: 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 many cases, but fail qualitatively in others.
authors.affiliation: Afdeling Theoretische Chemie, Scheikundig Laboratorium der Vrije Universiteit, De Boelelaan 1083, NL-1081 HV, Amsterdam, The Netherlands. m.van.faassen@few.vu.nl
authors.forename: Meta
authors.initials: M
authors.lastname: van Faassen
authors.forename: Kieron
authors.initials: K
authors.lastname: Burke