Neighboring clusters centers

As described in Section 2.3, the hexagon tiling is constructed by drawing lines connecting neighboring cluster centers. This stiU holds for each individual position of the phason line shown in Figs 9(a)-9(d). However, this does not imply that a vertex jump corresponds to the movement of a complete cluster from the initial to... 

The algorithm originally proposed by Moody and Darken (1989) uses >means clustering to determine the centers of the clusters. The hypersphere around each cluster center is then determined to ensure sufficient overlap between the clusters for a smooth fit by criteria such as the P-nearest neighbor heuristic,... 

DFT calculations on the model compound Cu6I6(SPhCH3)6 in its triplet state predict that the SHOMO localizes the spin density mainly on one Cu atom and its three iodo neighbors with the rest on one -SPh fragment, whereas it is rather delocalized over the Cu and I atoms in the HOMO (Fig. 32). The SHOMO is located at -0.042 a.u. above the HOMO (-0.125 a.u.). The simple arithmetic difference between the two levels suggests that the radiative relaxation should occur in the vicinity of 550 nm, which fits the experimentally observed maxima (Fig. 31). So the first theoretical study confirms a cluster-centered excited state as responsible for the observed emission, similar to other Cu4I4-containing species.146... 

The accessible deepness of donor centers extraction remains to be relatively small (probably, no more than several oxide lattice constants) because of its limitation by the low diffusion of oxygen, which is necessary for the oxidation of donor centers. To explain the experimentally observed appearance of a rather small concentration of relatively big Ag particles on the Ti02 electrodes, account must be given to the possibility of the lateral electron transfer from the neighboring donor centers, that is the electrochemical mechanism being of widespread occurrence in the processes of the chemical deposition of metals. In any case, metal nanoparticles deposited via the interaction of semiconductor donor centers with soluble metal ions prove to be localized at the sites of the electrode surface exposure of donor centers including continuous donor clusters. 

Supported polynuclear metal complexes have been formed on Si02, AI2O3, and MgO . The supported clusters catalyze alkene isomerization and CO hydrogenation. The supported metal clusters are of interest because they have unique structures with neighboring metal centers, intermediate between supported mononuclear metal complexes and metal crystallites. Catalysts in this class may offer interesting selectivities for reactions such as CO hydrogenation, but they are limited by their lack of stability. 

A f/oro-mthenacyclopentadiene complex 55 was obtained by the reaction of 7 with linear alkanes (Equation (18))." During this reaction, six C-H bonds of alkane were successively cleaved. Such multiple C-H bond cleavage was rationalized by the cooperative action of the neighboring ruthenium centers of the ttimetallic framework, which promotes the incorporation of alkane into the reaction field of the cluster. Such closo-typc metallacyclopentadiene complexes have been intensively studied using carbonyl clusters, and often prepared by the coupling reaction between the two alkyne ligands of the bis(/r3-7 ( )-alkyne) complex, so-called violet isomer.The /i3-sulfido complex 9 obtained by the reaction of 7 with thiophenol also reacts with alkane to yield a /ts-alkylidyne complex. ... 

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