A new cluster source for the generation of binary metal clusters

Abstract

A new thermal, supersonic cluster source for the investigation of binary metal cluster formation at thermodynamically well-defined expansion conditions is described. The source consists of two separately heatable cartridges. A first cartridge can be heated up to 1220 K and the second high temperature cartridge reaches maximal temperatures of 1800 K. A temperature difference of 1000 K between the two cartridges can be maintained for at least 3 h. Clustering occurs upon supersonic expansion from a conical nozzle. This cluster source has two main applications: (a) the generation of mixed metal clusters and (b) the investigation of pure metal clusters at various expansion conditions. The performance and applications of this source are illustrated by presenting results of the heterocluster formation of mixed sodium/gold and sodium/silver heteroexpansions. In addition, the influence of the oven parameters on the internal temperatures of the generated clusters is illustrated with the example of Na2.

Catalysis with Supported Size-selected Pt Clusters

“…In this respect the laser ablation cluster source is one method of choice. Cluster catalysts reported in this work have all been generated using a high frequency laser evaporation source [25,17,18,38]. Thus, only the performance and mode of operation of this type of source (with Pt clusters as example) is described.…”

“…The first experiments of synthesizing such well defined agglomerates in the gas phase were reported in the early 1980s' [12,13,14,15,16] and revealed particular properties for each cluster size. Using these well defined particles as heterogeneous catalyst materials was made possible only with significant development of the experimental means [17,18].…”

“…An electron from a higher shell fills the hole and the energy thereby released is emitted as a quantum of characteristic radiation (X-ray fluorescence) 18 , fig. 3.2.3a.…”

“…Generally, the potentials of the deflector rods are applied in such way, that cationic clusters are directed towards the direction of the used QMS. These clusters are focused into the QMS by an additional stack of einzel lenses (lenses 16,17,18). Depending on the bender settings, already a mass-preselection is achieved [219], as only clusters with a certain mass-to-charge ratio ( m /z ) can pass the bender on an appropriate trajectory through the exit hole into the following ion optics [20,38,39].…”

Cluster Assembled Sb Films: Studies On Structure, Surface And Optical Properties

“…Such cluster generated nanomaterials can have structures in between those of amorphous and crystalline bulk phases with short range order which is controlled by their size, but without any long range order. Several novel methods (Melinon et al, 1995;Maruno et al, 1998;Kanayama and Murakami, 1997;Murakami, 1997;Heiz et al, 1997;Ludwig et al, 1994) have been developed to produce these cluster assembled materials in a controlled manner, these include techniques such as Ion Traps (Kanayama and Murakami, 1997), Molecular Beam Deposition (MBD) (Fuchs et al, 1991a,b), Spark Processes (Ludwig et al, 1994) and Low Energy Cluster Beam Deposition (LECBD) (Melinon et al, 1995;Sattler et al, 1980). Of these, LECBD is one of the most convenient methods for generating these nano-phase material.…”