%0 Journal Article
%A Haags, Anja
%A Brandstetter, Dominik
%A Yang, Xiaosheng
%A Egger, Larissa
%A Kirschner, Hans
%A Gottwald, Alexander
%A Richter, Mathias
%A Koller, Georg
%A Bocquet, François C.
%A Wagner, Christian
%A Ramsey, Michael G.
%A Soubatch, Serguei
%A Puschnig, Peter
%A Tautz, F. Stefan
%T Tomographic identification of all molecular orbitals in a wide binding-energy range
%J Physical review / B
%V 111
%N 16
%@ 2469-9950
%C Woodbury, NY
%I Inst.
%M FZJ-2025-02241
%P 165402
%D 2025
%X In the past decade, photoemission orbital tomography (POT) has evolved into a powerful tool to investigate the electronic structure of organic molecules adsorbed on surfaces. Here we show that POT allows for the comprehensive experimental identification of all molecular orbitals in a substantial binding energy range of more than 10 eV. Making use of the angular distribution of photoelectrons as a function of binding-energy, we exemplify this by extracting an orbital-resolved projected density of states for 15 𝜋 and 23 𝜎 orbitals from the experimental data of the prototypical organic molecule bisanthene (C28⁢H14) on a Cu(110) surface. These experimental results for an essentially complete set of orbitals within the given binding-energy range serve as stringent benchmarks for electronic structure methods, which we illustrate by performing density functional calculations employing four frequently used exchange-correlation functionals. By computing the respective molecular-orbital-projected densities of states, a one-to-one comparison with experimental data for an unprecedented number of 38 orbital energies became possible. The quantitative analysis of our data reveals that the range-separated hybrid functional HSE performs best for the investigated organic/metal interface. At a more fundamental level, the remarkable agreement between the experimental and the Kohn-Sham orbital energies over a binding-energy range larger than 10 eV suggests that—perhaps unexpectedly—Kohn-Sham orbitals approximate Dyson orbitals, which would rigorously account for the electron extraction process in photoemission spectroscopy but are notoriously difficult to compute, in a much better way than previously thought.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:001460182600007
%R 10.1103/PhysRevB.111.165402
%U https://juser.fz-juelich.de/record/1041428