Design and Construction of a Molecular Beamline for Cluster Catalysis Studies

Metal and metal oxide nanoparticles are widely used in heterogeneous catalysis. In order to determine how these catalysts function and in order to find new catalysts, model systems can be used to provide experimental and computational insight. One such model system is a cluster which contains <100 atoms allowing for ease of calculation. In this work a molecular beamline was constructed in order to produce a wide range of these clusters and control their composition on an atom-by-atom level. These clusters could then be deposited onto a substrate in vacuum and studied via multiple techniques including TPD, XPS, UPS, LEED, and STM, allowing for the study of not only the cluster’s composition but their reactivity to a range of reactants in a range of reaction environments. In the process of designing the instrument, novel tools and parts were developed and manufactured to push the capabilities of the instrument forward and are discussed in detail. The instrument was tested and found to meet the three design goals of a molecular beamline that can 1) produce a large range of clusters varying in size and composition of a magnitude that can be deposited and studied in a timely fashion, 2) mass select the clusters with a resolution capable of resolving the elements in the cluster, and 3) bring to bear a variety of analytical techniques to study the cluster’s composition and catalytic capabilities