Molecular Orbital Shift of Perylenetetracarboxylic-Dianhydride

TL;DR

This study investigates how the adsorption phases of Perylenetetracarboxylic-Dianhydride on Au(788) influence its molecular orbitals, revealing phase-dependent orbital energies and the role of hydrogen bonding.

Contribution

It provides the first detailed correlation between adsorption phases and molecular orbital shifts of Perylenetetracarboxylic-Dianhydride on gold surfaces using combined experimental and theoretical methods.

Findings

Three coexisting adsorption phases identified.

Orbital energies vary with adsorption phase.

Hydrogen bonds likely cause orbital shifts.

Abstract

Using low-temperature scanning tunneling microscopy we find that perylenetetracarboxylic-dianhydride on Au(788) exhibits three coexisting adsorption phases. Single-molecule tunneling spectroscopy reveals orbital energies, which differ in the different adsorption phases. Density functional theory calculations associate the experimentally observed submolecular corrugation to the spatial distribution of the second-to-lowest unoccupied molecular orbital. We tentatively attribute the orbital shifts to a varying number of hydrogen bonds.