EPJ manuscript No. (will be inserted by the editor) Photoionisation using Kohn-Sham wave functions

Abstract. The determination of photoionisation cross sections using the Kohn-Sham wave functions from accurate density functional theory (DFT) calculations is considered. The continuum electrons wave function is specied by its momentum measurable in the detector rather than xed angular momentum and energy. The method is applied to the test case of a water molecule, where the DFT calculations show excellent agreement to experiment in the ionisation energies if a vertical transition is considered. The continuum electron is described by an analytical wave function and the matrix elements are calculated in both in length and velocity form of the dipole operator. The cross sections agree well with the experiment in particular for the velocity form. PACS. 31.15.Ew Density-functional theory { 33.80.Eh Autoionization, photoionization, and photodetach-ment