Recent wide-field photometric surveys (Lee et al.; Pancino et al.) have shown the existence of a previously unknown metal-rich ([F e/H] ≃ −0.6) stellar population in the galactic globular cluster ω Centauri. The discovery of this new component, which comprises only a small percentage (∼ 5%) of the entire cluster population, has added a new piece to the already puzzling picture of the star forma...

With the ultimate aim of distinguishing between various models describing the formation of galaxy halos (e.g. radial or multi-phase collapse, random mergers), we have completed a spectroscopic study of the globular cluster system of M31. We present the results of deep, intermediate-resolution, fibre-optic spectroscopy of several hundred of the M31 globular clusters using the Wide Field Fibre Op...

Simultaneous reduction of WCl6 and CCl4 with bismuth metal at 400 degrees C affords a black solid, from which the new cluster [W6CCl18]2- is extracted into aqueous HCl. The cluster is isolated in 34% yield as (Bu4N)2[W6CCl18] and features a metal-metal bonded W6 trigonal prism centered by a carbon atom and surrounded by 12 edge-bridging and 6 terminal chloride ligands. A cyclic voltammogram of ...

DNA-protected silver clusters (AgN-DNA) possess unique fluorescence properties that depend on the specific DNA template that stabilizes the cluster. They exhibit peak emission wavelengths that range across the visible and near-IR spectrum. This wide color palette, combined with low toxicity, high fluorescence quantum yields of some clusters, low synthesis costs, small cluster sizes and compatib...

The chemical reactions of transition metal clusters in the gas phase have aroused considerable scientific interest and are also of critical scientific importance. For example, these reactions are involved in the synthesis of single-walled carbon nanotubes, which are considered ideal materials because of their outstanding properties. Alcohol catalytic chemical vapor deposition (ACCVD) is one of ...

For a sample of some 400 red giants in the chemically inhomogeneous globular cluster ! Centauri we report correlations between the radial velocities of Mayor et al. (1997), which are accurate to <1 km s ?1 , and the calcium abundances of Norris et al. (1996), which have internal accuracy 0.06 dex. We nd that the 20% metal-rich tail of the Ca/H] distribution, as well as being more centrally-conc...

Reaction between Cp*TaCl4 (Cp* = h5-C5H5) and BH3·thf at 40 °C yields the pale red electronically unsaturated cluster Cp*TaCl2B4H8 1 which despite having two electrons fewer than the seven pairs required for the observed square pyramidal geometry is stable in air; viewed as a cluster, 1 is the first example of an unsaturated cluster containing a single metal atom; viewed as a chiral 16-electron...

these are notes from introductory survey lectures given at the institute for studies in theoretical physics and mathematics (ipm), teheran, in 2008 and 2010. we present the definition and the fundamental properties of fomin-zelevinsky’s cluster algebras. then, we introduce quiver representations and show how they can be used to construct cluster variables, which are the canonical generators of ...

Many metal alloys are susceptible to corrosion, particularly after processing steps such as welding. Chemical vapor deposition (CVD) is an effective way to modify metal surfaces and impart specific physical and chemical properties. A hydrophobic, nanosegmented silicon oxide coating derived from the discrete cluster molecule H8Si8O12 has been shown to chemisorb to 302 and 304 stainless steel. To...

The transport properties of films assembled from metal nanoclusters can be significantly different from the metals in their bulk or thin film forms due to quantum confinement effects and several competing energy and length scales. For a film composed of metal nanoclusters as its building blocks, the cluster size and the inter-cluster separation are parameters that can be varied experimentally. ...