Efficient Scheme for Calculation of Low-Energy Electron-Diffraction Intensities in the Presence of Large Superlattices, with Application to the Structural Analysis of Benzene Adsorbed on Rh(111)

Abstract

A powerful calculational low-energy electron-diffraction scheme is introduced for super lattices with unit cells of any size: beam-set neglect. It is applied in the first structural analysis from low-energy electron-diffraction intensities of a large molecule, benzene, adsorbed on a single-crystal metal surface, Rh(111). In a $\left(\{3,1\}\{1,3\}\right)$ lattice, benzene is found to lie flat on the surface, centered over hcp-type hollow sites. A planar, possibly distorted ${\mathrm{C}}_6$ ring is found with Rh-C bond lengths of 2.35±0.05 Å.