Detailed Structure of Adsorbed Fullerenes: A Joint LEED, LEEM and Total-energy Study

Description

The goal of this project is to determine the atomic-level structure of nanoparticles, e.g. C60 molecules, adsorbed on single-crystal surfaces, e.g. Cu(111) and Pt(111). Structural information to be obtained includes adsorbate orientation, adsorbate-substrate distances, and induced distortions. Such results will be invaluable in predicting nanoparticle structure, properties, and behaviour, relevant to many technologies in Hong Kong and elsewhere.The work will be based on two complementary experimental techniques, using quantitative analysis of measurements from both low-energy electron diffraction (LEED) and low-energy electron microscopy (LEEM). LEED permits measuring diffraction data for analysis over a wide surface area; LEEM in addition allows a microscopic inspection of the adsorbate’s local ordering.Detailed LEED analysis normally involves testing many structures with multiple-scattering calculations. Using total-energy calculations this search will be restricted to relatively few candidates. In addition, because of the complexity of nanostructures, new high-efficiency LEED-computational methods will be applied to this analysis, as well as a novel evolutionary algorithm for global searching of the optimal structure.The total-energy calculations will furthermore explain the interactions between the nanoparticles and the supporting substrate, through their electronic structure: these are arguably at the core of much of nanoscience and technology.