Figure 5: Reconstructed HOMO and LUMO orbitals of PTCDA in a real space representation.

(a) 3D images of the HOMO in top view and side view respectively. (b) The same for the LUMO. Red (blue) regions indicate isosurfaces corresponding to a constant positive (negative) value of the wave function. (c and d) Vertical line scans through the HOMO and LUMO wave functions , respectively, at the positions indicated in green. The red solid lines and the orange symbols are reconstructed from the raw measurement data extrapolated up to k_max=24 Å⁻¹ (red line), 8 Å⁻¹ (orange triangles) or 6 Å⁻¹ (orange circles), respectively, while the black dashed lines are based on a plane wave fit when performing the reconstruction. The insets in (c) and (d) show zoomed regions around the maximum electron density . Here, the solid (dashed) blue lines are vertical line scans through the DFT HOMO and LUMO orbitals of a free-standing (adsorbed) PTCDA molecule which are compared with the reconstructed orbitals.