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Title: Ultra-nonlocality in density functional theory for photo-emission spectroscopy

We derive an exact expression for the photocurrent of photo-emission spectroscopy using time-dependent current density functional theory (TDCDFT). This expression is given as an integral over the Kohn-Sham spectral function renormalized by effective potentials that depend on the exchange-correlation kernel of current density functional theory. We analyze in detail the physical content of this expression by making a connection between the density-functional expression and the diagrammatic expansion of the photocurrent within many-body perturbation theory. We further demonstrate that the density functional expression does not provide us with information on the kinetic energy distribution of the photo-electrons. Such information can, in principle, be obtained from TDCDFT by exactly modeling the experiment in which the photocurrent is split into energy contributions by means of an external electromagnetic field outside the sample, as is done in standard detectors. We find, however, that this procedure produces very nonlocal correlations between the exchange-correlation fields in the sample and the detector.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [4]
  1. Department of Physics, Nanoscience Center, University of Jyväskylä, Survontie 9, 40014 Jyväskylä (Finland)
  2. Dipartimento di Fisica, Universitá di Roma Tor Vergata, Via della Ricerca Scientifica, 00133 Rome (Italy)
  3. (Italy)
  4. (ETSF), Louvain-la Neuve (Belgium)
Publication Date:
OSTI Identifier:
22253428
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 18; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CURRENT DENSITY; DENSITY FUNCTIONAL METHOD; ELECTROMAGNETIC FIELDS; EMISSION SPECTROSCOPY; KINETIC ENERGY; PERTURBATION THEORY; SIMULATION; SPECTRAL FUNCTIONS