The structural properties of free nanoclusters are reviewed. Special attention is paid to the interplay of energetic, thermodynamic, and kinetic factors in the explanation of cluster structures that are actually observed in experiments. The review starts with a brief summary of the experimental methods for the production of free nanoclusters and then considers theoretical and simulation issues, always discussed in close connection with the experimental results. The energetic properties are treated first, along with methods for modeling elementary constituent interactions and for global optimization on the cluster potential-energy surface. After that, a section on cluster thermodynamics follows. The discussion includes the analysis of solid-solid structural transitions and of melting, with its size dependence. The last section is devoted to the growth kinetics of free nanoclusters and treats the growth of isolated clusters and their coalescence. Several specific systems are analyzed.

/pdf/structural-properties-of-nanoclusters-energetic-56vj4t3ucw.pdf

Structural properties of nanoclusters: Energetic, thermodynamic, and kinetic effects

Synthesis, properties, and applications of magnetic iron oxide nanoparticles

Fundamentals of H2 Binding and Reactivity on Transition Metals Underlying Hydrogenase Function and H2 Production and Storage

The key methods for the preparation of magnetic nanoparticles are described systematically. The experimental data on their properties are analysed and generalised. The main theoretical views on the magnetism of nanoparticles are considered.

https://iopscience.iop.org/article/10.1070/RC2005v074n06ABEH000897/pdf

Magnetic nanoparticles: preparation, structure and properties

Digital information processing in molecular systems.

A systematic theoretical study of the equilibrium geometries and total energies of Cr encapsulated in Si clusters reveals that $\mathrm{Cr}{\mathrm{Si}}_{12}$ is more stable than its neighbors. The origin of this enhanced stability is consistent with the 18-electron sum rule commonly used in the synthesis of stable chemical complexes, and may provide a criterion for a systematic search of magic numbers in metalloinorganic clusters. The $6{\ensuremath{\mu}}_{\mathrm{B}}$ magnetic moment of the caged Cr atom, the largest among the $3d$ transition metal atoms, is completely quenched. This effect of caging on the properties of transition metal atoms may lead to the synthesis of novel cluster based materials.

Magic numbers in metallo-inorganic clusters: chromium encapsulated in silicon cages.

The electronic and geometrical structures of the ground and excited states of the 3d-metal dioxides ScO2, TiO2, VO2, CrO2, MnO2, FeO2, CoO2, NiO2, CuO2, and ZnO2 along with their singly charged negative ions have been calculated using the density functional theory with generalized gradient approximation for the exchange-correlation potential. We have considered oxo, peroxo, and superoxo isomers in both neutral and anionic series. The ground states of all 3d-metal dioxides and their anions possess oxo forms, except for copper dioxide, which prefers a superoxo form. All the dioxides have a large number of isomers closely spaced in total energy. The champion, FeO2-, possesses five isomers within an energy range of 0.35 eV. The energy gap between oxo, peroxo, and superoxo isomers decreases along the series from TiO2 to ZnO2. ScO2 has peroxo and superoxo isomers which are close in total energy to its oxo ground state. The electron affinities are computed for all types of isomers and are compared to available e...

Systematic Study of Oxo, Peroxo, and Superoxo Isomers of 3d-Metal Dioxides and Their Anions

Calculations based on density-functional theory show that the stability and magnetic properties of small Mn clusters can be fundamentally altered by the presence of nitrogen. Not only are their binding energies substantially enhanced, but also the coupling between the magnetic moments at Mn sites remains ferromagnetic irrespective of their size or shape. In addition, these nitrogen-doped Mn clusters carry giant magnetic moments ranging from $4{\ensuremath{\mu}}_{\mathrm{B}}$ in MnN to $22{\ensuremath{\mu}}_{\mathrm{B}}$ in $\mathrm{M}{\mathrm{n}}_{\mathrm{5}}\mathrm{N}$. It is suggested that the giant magnetic moments of ${\mathrm{M}\mathrm{n}}_{x}\mathrm{N}$ clusters may play a key role in the ferromagnetism of Mn-doped GaN which exhibit a wide range (10--940 K) of Curie temperatures.

Giant magnetic moments of nitrogen-doped Mn clusters and their relevance to ferromagnetism in Mn-doped GaN.

Origin of the unusual stability of MnO4

Theoretical studies of the ground-state geometries, electronic structure, binding energies, ionization potentials, and magnetic moments of Rh{sub n} (n=2{endash}13) clusters have been carried out using a combination of molecular-dynamics and {ital ab initio} density-functional scheme including gradient corrections. For clusters containing less than eight atoms, the ground states have been determined by starting from several random configurations and minimizing the geometry using first-principles density-functional calculations. For larger clusters, the initial geometries were obtained via molecular-dynamics simulations based on a tight-binding many-body potential and reoptimized using the density-functional approach. The ground-state structures are all compact arrangements and the clusters containing 8, 9, 10, 11, and 12 atoms resemble icosahedral fragments. The clusters are shown to undergo progression of magnetic behaviors with size. While most clusters are ferromagnetic with varying magnetic moments, Rh{sub 4} and Rh{sub 6} are found to have nonmagnetic states that are nearly degenerate with ferromagnetic states. The variation in the magnetic moments is shown to be intimately linked to the electronic structure. {copyright} {ital 1999} {ital The American Physical Society}

B. K. Rao

Papers

Magic numbers in metallo-inorganic clusters: chromium encapsulated in silicon cages.

Systematic Study of Oxo, Peroxo, and Superoxo Isomers of 3d-Metal Dioxides and Their Anions

Giant magnetic moments of nitrogen-doped Mn clusters and their relevance to ferromagnetism in Mn-doped GaN.

Origin of the unusual stability of MnO4

Electronic structure and magnetism of Rh n ( n = 2 – 1 3 ) clusters