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Within the last years, a fundamental understanding of nanoscaled materials has become a tremendous challenge for any technical applications. For magnetic nanoparticles, the research is stimulated by the effort to overcome the superparamagnetic limit in magnetic storage devices. The physical properties of small particles and clusters in the gas phase, which are considered as possible building blocks for magnetic storage devices, are usually sizedependent and clearly differ from both the atom and bulk material. For any technical applications, however, the clusters must be deposited on surfaces or embedded in matrices. The contact to the environment again changes their properties significantly. Here, we will mainly focus on the fundamental electronic and magnetic properties of metal clusters deposited on surfaces and in matrices. This, of course, requires a well-defined control on the production of nanoparticles including knowledge about their structural behaviour on surfaces that is directly related to their www.elsevier.com/locate/surfrep Surface Science Reports 56 (2005) 189-275 $ This work is based on results of the EU ''AMMARE'' project within the Fifth Framework programme coordinated by Antonis N. Andriotis, Heraklion, Greece.

The local and average orbital moments of transition-metal (TM) clusters are determined bridging the gap between atomic Hund's rules and solid-state quenching. A remarkable enhancement of is revealed in agreement with recent measurements. In small Ni(N) (N< or =10), represents (20-40)% of the total magnetization and is therefore crucial for the comparison between theory and experiment. Larger clusters (N> or =150) show nearly bulklike quenching at the interior but retain a considerable surface enhancement. Trends for different TM's are discussed.

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Inorganic chemistry Z 0100Magnetic and Structural Properties of Isolated and Assembled Clusters -[227 refs.]. -(BANSMANN, J.; BAKER, S. H.; BINNS, C.; BLACKMAN, J. A.; BUCHER, J.-P.; DORANTES-DAVILA, J.; DUPUIS, V.; FAVRE, L.; KECHRAKOS, D.; KLEIBERT, A.; et al.; Surf. Sci. Rep. 56 (2005) 6-7, 189-275; Inst. Phys., Univ. Rostock, D-18051 Rostock, Germany; Eng.) -Schramke 52-215

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The ground-state magnetic properties and related electronic properties of small Fe~clusters are calculated by using an spd-band model Hamiltonian in the unrestricted Hartree-Fock approximation. Results are given for the average magnetic moment per atom pN, the spin-polarized charge distribution within the cluster, and the sp and d electronic density of states. The calculated p~(N ( 15) are larger than the bulk value pg = 2.21@,. Small local sp magnetic moments are obtained, which in most cases are opposite to the dominant d magnetic moments (p, "-O. lpga, ps 2.5 -2. gpss).The role of sp electrons and spd hybridization is discussed particularly, by comparison with previous d-band model calculations. The main quantitative effect obtained by including the sp electrons in the self-consistent calculations is a reduction of about 10% of the value of P~.