Crystallography of Clusters

Crystallographic characterisation of small metal clusters, oxide clusters of Cu and molecular clusters of CdS in the size range of 1 to 10 nm diameter is performed by using HRTEM. This is achieved by comparing experimentally obtained and digitised images and their calculated power spectra with computer simulations performed by the multislice technique for relevant cluster models. Typical structures are being discussed, such as fcc cuboctahedra, hexagonal structures, multiply twinned particles such as decahedra and icosahedra with 5-fold symmetries. Following a brief outline of the multislice technique, the calculations were performed for typical orientations depending on the different models. For most structural orientations, examples of experimental results are given. Finally, two examples for the reduction of oxidised Cu particles under the electron beam of high dose are presented.