Adsorption geometry and electronic structure of a charge-transfer-complex: TTF-PYZ₂ on Ag(110)

Abstract

We study electronic properties and adsorption geometries of the molecular charge-transfer-complex tetrathiafulvalene-dipyrazine on Ag(110). Using a combination of angle-resolved photoemission and electron diffraction, supported by DFT-based simulations, renders a comprehensive picture of this interesting system. We find low interaction between the substrate and the molecule and thus little changes of the molecular geometry upon adsorption, as compared to the free gas phase molecule. Five electronic valence states can be unambiguously assigned owing to their distinctive photoemission patterns. The molecules adsorb aligned with the Ag rows in the first layer, while they are slightly rotated in the second layer. Additional intensity of the molecular photoemission signal near the Fermi energy indicates partial charge-transfer into formerly unoccupied states, most likely of intermolecular origin.

Donors, acceptors, and a bit of aromatics: electronic interactions of molecular adsorbates on hBN and MoS2 monolayers

“…Exceptions concern a concave bending of TTF of about 11° towards the substrate (see Fig. 1b), in contrast with previous results on metallic surfaces, 72,73 where the molecule bends in a convex fashion due to the strong interactions with the metal electronic charge density. Furthermore, 2T undergoes a backbone “twist” with a dihedral angle of 7° (Fig.…”

Demonstrating the Impact of the Adsorbate Orientation on the Charge Transfer at Organic–Metal Interfaces

“…However, when utilizing the connection between ARUPS intensity maps and the Fourier transform of molecular orbitals, known as photoemission tomography (PT), 23 ARUPS has been utilized to simultaneously reveal the electronic and geometric structure for a number of organic adsorbate systems. 16 , 24 − 29 …”

“…While well-known surface investigating techniques such as scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED) primarily focus on determining structural aspects, (angle-resolved) ultraviolet photoemission spectroscopy (ARUPS) traditionally reveals the electronic (band) structure of the adsorbate layers. However, when utilizing the connection between ARUPS intensity maps and the Fourier transform of molecular orbitals, known as photoemission tomography (PT), ARUPS has been utilized to simultaneously reveal the electronic and geometric structure for a number of organic adsorbate systems. ,− …”

Orbital Mapping of Semiconducting Perylenes on Cu(111)

“…A number of adsorption effects have been derived from ARPES momentum mapping. For instance, chemical modifications in the molecule have been identified, , and in several studies, geometrical parameters of the adsorbate could be determined from the orbital momentum mapping including azimuthal orientations of molecules, , inter-ring torsion angles, , and molecular tilt angles . Our approach has been to perform a multi-technique experimental investigation of complex PAH molecules with similar geometries.…”