Embedded cluster

The electron density, pj, of the embedded cluster/adsorbate atoms is calculated using quantum chemistry methods (HF, PT, multireference SCF, or Cl). The initial step in this iterative procedure sets to zero,... 

VIsser O, Vlssoher L, Aerts P J C and NIeuwpoort W C 1992 Moleoular open shell oonflguratlon Interaotlon oaloulatlons using the Dlrao-Coulomb Flamlltonlan the f -manlfold of an embedded cluster J. Chem. Phys. 96 2910-19... 

PIsanI C, Orlando R and Cora F 1992 On the problem of a suitable definition of the cluster In embedded-cluster treatments of defects In crystals J. Chem. Phys. 97 4195-204... 

Pisani C 1993 Embedded-cluster techniques for the quantum-mechanical study of surface reactivity J. Mol. Catal. 82 229... 

Whitten J L 1993 Theoretical studies of surface reactions embedded cluster theory Chem. Phys. 177 387-97... 

Duarte H A and Salahub D R 1998 Embedded cluster model for chemisorption using density functional calculations oxygen adsorption on the AI(IOO) surface J. Chem. Phys. 108 743... 

Ravenek W and Geurts EMM 1986 Hartree-Fock-Slater-LCAO implementation of the moderately large-embedded-cluster approach to chemisorption. Calculations for hydrogen on lithium (100) J. Chem. Phys. 84 1613-23... 

Fukunishi Y and Nakatsu] H 1992 Modifications for ab initio calculations of the moderately large-embedded-cluster model. Hydrogen adsorption on a lithium surface J. Chem. Phys. 97 6535-43... 

Casassa S and Pisani C 1995 Atomic-hydrogen interaction with metallic lithium an ab /M/o embedded-cluster study Phys. Rev. B 51 7805... 

Ellis D E, Benesh G A and Byrom E 1978 Self-consistent embedded-cluster model for magnetic impurities p -NiAl J. Appl. Phys. 49 1543... 

Kruger S and Rdsch N 1994 The moderately-large-embedded-cluster method for metal surfaces a density-functional study of atomic adsorption J. Phys. Condens Matters 8149... 

Head J D and Silva S J 1996 A localized orbitals based embedded cluster procedure for modeling chemisorption on large finite clusters and infinitely extended surfaces J. Chem. Phys. 104 3244... 

The above methods all assume that a clear spatial distinction can be made between toxic and nontoxic compounds. However, it is sometimes found that toxic compounds form a cluster embedded in a milieu of nontoxic compounds. In such cases, a different technique, embedded cluster modeling, can be used [77]. Cronin [78] has used the technique to model eye irritation data. 

Worth AP, Cronin MTD. Embedded cluster modelling a novel QSAR method for generating elliptic models of biological activity. In Balls M, van Zeller A-M,... 

Well-defined nanoclusters (w 10-100 A diameter) of several metals have been prepared via the polymerization of metal-containing monomers. The synthetic approach involves the block copolymerization of a metallated norbornene with a hydrocarbon co-monomer which is used to form an inert matrix. Subsequent decomposition of the confined metal complex affords small clusters of metal atoms. For example, palladium and platinum nanoclusters may be generated from the block copolymerization of methyl tetracyclododecane (223) with monomers (224) and (225) respectively. 10,611 Clusters of PbS have also been prepared by treating the block copolymer of (223) and (226) with H2S.612 A similar approach was adopted to synthesize embedded clusters of Zn and ZnS 613,614... 

The synthesis of technologically interesting ROMP materials using (233) includes the preparation of molecular wires,701 liquid-crystal polymers,702,703 chiral supports for catalysis,704 redox-active macromolecules,705 photochromic materials706 and embedded clusters of CdSe.707 Polymers... 

Thus, to the best of our knowledge, there is a lack of embedding cluster studies on the yttrium ceramics where with a sufficient precision both aspects of the ECM were taken in account. In the study [44], we attempted to fill such a gap and carried out the electronic structure calculations of the YBa2Cu307 ceramics at the Moller-Plesset level with a self-consistent account of the infinite crystal surrounding to the quantum cluster. The Gaussian basis set employed (6-31IG) was larger than those used in previous cluster calculations [16,20,22,29]. 

Lada, C. J. and Lada, E. A. (2003) Embedded clusters in molecular clouds. Annual Reviews of Astronomy and Astrophysics, 41, 57—115. 

Abstract. An embedded-cluster approximation is adopted for simulating the heterolytic dissociation of hydrogen at two intrinsic defects on the (001) surface of magnesium oxide the isolated anion vacancy, and the tub divacancy. The dissociation process is shown to be critically dependent on the structure of the electrostatic field at the surface both as concerns energetics and final configuration. 

Figure 1. Embedded clusters used for simulating the anion vacancy (left) arid the tub divacancy (right). Oxygen arid magnesium ions are represented by white arid light grey circles respectively. The O ions at which the protori is bound are marked with Greek letters. The position of the missing oxygen is marked with V. The two Mg ions marked with an asterisk are included only when protori adsorption at O(fi) is considered.

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