Exploring the Bonding of Large Hydrocarbons on Noble Metals: Diindoperylene on Cu(111), Ag(111), and Au(111)

TL;DR

This study combines X-ray standing wave measurements and advanced density functional theory calculations to accurately determine the bonding distances and energies of diindenoperylene on noble metal surfaces, revealing substrate-dependent vdW interactions.

Contribution

It provides benchmark data and validates a computational method for large organic molecules on noble metals, highlighting the importance of substrate response in vdW interactions.

Findings

Excellent agreement between experiment and theory for bonding distances

vdW contribution to adsorption energy varies with substrate

PBE+vdW^{surf} method accurately predicts adsorption properties

Abstract

We present a benchmark study for the adsorption of a large pi-conjugated organic molecule on different noble metal surfaces, which is based on X-ray standing wave (XSW) measurements and density functional theory calculations with van der Waals (vdW) interactions. The bonding distances of diindenoperylene on Cu(111), Ag(111), and Au(111) surfaces (2.51 A, 3.01 A, and 3.10 A, respectively) determined with the normal incidence XSW technique are compared with calculations. Excellent agreement with the experimental data, i.e. deviations less than 0.1 A, is achieved using the Perdew-Burke-Ernzerhof functional with vdW interactions that include the collective response of substrate electrons (PBE+vdW^{surf} method). Noteworthy, the calculations show that the vdW contribution to the adsorption energy increases in the order Au(111) < Ag(111) < Cu(111).