Heteroatom and Alloy Clusters

Binary aggregates are usually called heteroatom clusters when m = 1 (or some- 

Early interest in heteroatom clusters having alkali metals as the host was academic rather than dictated by precise observations. The main question regarded the extent to which the jellium-derived shell model retained its validity. However, this question was approached on the basis of oversimplified structural models in which the heteroatom (typically a closed-shell alkali-earth such as Mg) was located at the center of the cluster [235, 236]. In this hypothetical scheme, the perturbation of the electronic structure relative to that of the isoelectronic alkali cluster is somewhat trivial for instance, in the Na Mg system the presence of Mg would only alter the sequence of levels of the shell jellium model from Is, Ip, Is, 2s,. .. (appropriate to sodium clusters) to Is, Ip, 2s, Id,. .. (see also [236]). This would lead to the prediction that Na6Mg and NasMg are MNs. 

Finally, let us mention a recent calculation of the special heteroatom cluster AliaNa [243] (see Appendix C), which corresponds to a 40e system, namely, an MN of the shell model, and is isoelectronic to the Ali3 anion discussed in Section 3.8. The result is not 

The extension of the theory to time-dependent phenomena is (slowly) expanding the reach of DFT to the domain of optical and spin spectroscopies. This advance is expected to greatly increase the value of DFT computations in general as a guide in the interpretation of experimental data. At the same time, it will enhance the chance of having benchmarks and obtaining useful feedback for the theoretical and computational schemes. 

An important impulse must come from experiments to Justify the use of large computer resources to investigate metal clusters, such as, for example, either the discovery of 

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