First-principles study of helium clustering at initial stage in ThO2

The clustering behavior of helium atoms in thorium dioxide has been investigated by first-principles calculations. The results show that He atoms tend to form a cluster around an octahedral interstitial site（OIS）. As the concentration of He atoms in ThO2 increases, the strain induced by the He atoms increases and the octahedral interstitial site is not large enough to accommodate a large cluster, such as a He hexamer. We considered three different Schottky defect（SD） configurations（SD1, SD2, and SD3）. When He atoms are located in the SD sites, the strain induced by the He atoms is released and the incorporation and binding energies decrease. The He trimer is the most stable cluster in SD1. Large He clusters, such as a He hexamer, are also stable in the SDs.

XPS STUDY ON Mo-Cu-S CLUSTERS

The binding energies of Mo,Cu,S and Br atoms in(NH4)2MoS4,[(n-Bu)4N]4[MoS4Cu6Br3] and [Mos4Cu6Br4(Py)4]n,were determined by usingXPS.The resul is revealed some eifferences in bonding properies ofthese three clusters.

Theoretical Study of Small Water Clusters of Sulfur Dioxide

The intermolecular clusters of sulfur dioxide with water, SO2（H2O）n （n = 2～5）, are studied by using B3LYP density functional theory and MP2 ab initio methods along with the large basis sets （6-311＋＋G（d,p） and aug-cc-pVDZ）. The equilibrium geometries, intermolecular binding energies, and anharmonic frequencies of the clusters are calculated and compared with those of pure water clusters and available experiments. SO2 tends to form cyclic hydrogen-bonded complexes with two or three water molecules. In the larger clusters, however, water molecules begin to retain the structure of pure water clusters and segregate from SO2. Infrared absorption assignments for the small clusters are discussed to resolve a possible incorrect assignment in a recent spectroscopic experiment on the clusters.

Mass Spectrometric Study of Clusters Produced by Laser Vaporization of Some Phosphates

The clusters generated by direct laser vaporization of KH2PO4 and Cu-3(PO4)(2) samples are studied by a TOF mass spectrometer. It is found that mainly the [K(KPO3)(n)]* cluster series is generated from KH2PO4 sample and it demonstrates obvious magic numbers, which are n=3, 6, 9, 12, 15. Direct laser vaporization of Cu-3(PO4)(2) sample produced [Cu(CuPO3)n]* cluster series as well as other series with the same building block of (CUPO3).

Regolith Geochemical Studies in Kimberlitic Terrain: A Case Study from Lattavaram Kimberlite Cluster, Eastern Dharwar Craton, Southern India

Utility of geochemistry in mineral exploration is known since more than half-a-century.In reconnaissance diamond exploration,regolith geochemistry is a well known tool worldwide and helps in distinguishing bedrock

AB INTIO THEORETICAL STUDY OF MIXED CLUSTER AICB

By uae of ab initio and analytic energy gradient method, twelve optimized electronic states of AICB,AIBC, BAIC in six geometric configurations are determined at all electron UHF(RHF) /6-31G level, their singles and doubles CI (CISD) energies are also obtained. The Stabillties for the atates of AICB have been investigated based on the vibrational analysis. binding energy and fragmentation energy. The ground state is 3∑+ of AICB (C∞. TAIC= 1.7497.,TBC=1.3511 A = 206.7, 799.5, 1802.9 cm-1, T=0), the second state is 1A' of AICB (Cs,TAIC=1.9162, TBC = 1.3154 A, ∠AICB=179。8307, =238.5, 575. 1,1767. 5.cm-1, T =2432.84 cm-1). The fragmentations of vallous States (fragmentation products are AIB,AIC, BC diatomic clusters. and Al, B, C free atoms) of AIBC, AICB. BAIC are discussed in detail.

A Density Functional Study of N-Doped TiO_2 Anatase Cluster

A systematic study on geometry, electronic structure and vibrational properties of N-doped TiO2 anatase cluster, within the framework of the density functional theory, has been performed in this work. The calculations confirmed that the most structures in substitutional model consist of a two-coordinate bridge structure and a three-coordinate hollow structure. The calculated results can well explain the red shift in N-doped TiO2 observed in experiments. The study provides an illustration for the N-doped anatase from the viewpoint of chemical bonding theory.

Studies of Atomic Structure and Physical Properties of Metal Clusters in MgO by HREM and Nano-probe Methods

Nanometer-sized metal clusters were prepared inside single crystalline MgO films by vacuum co-deposition of metals and MgO. The atomic structure was studied by high-resolution electron microscopy (HREM) and nm-area electron diffraction. The size of the clusters is ranging from 1 nm to 3 nm without those larger than 5 nm, and most of them have definite epitaxial orientations with the MgO matrix films. The character of the composite films is very much useful for the studies of various kinds of physical properties with anisotroPy. The physical properties such as electric transport, magnetic, optical absorption, sintering and catalytic ones were thus measured on the same samples analyzed by HREM by using high sensitivity apparatus with interest of clarifying the retationship between the atomic structure and physical properties

Study on cobalt-carbon and iron-sulfur mixed cluster complexes——Synthesis and conformational analysis of mixed cluster complexes [μ-p-CH_3C_6H_4C_2Co_2 (CO)_6 S](μ-RS)Fe_2(CO)_6

Through complexation reaction of arynyl Fe-S complexes A(μ-p-CH_3C_6H_4C≡CS)(μ- RS)Fe_2(CO)_6 with Co_2(CO)_6, eight mixed cluster complexes B[μ-p-CH_3C_6H_4C_2Co_2(CO)_6S](μ- RS)Fe_2(CO)_6 have been synthesized. Reactivity of the complexation reaction is approximately equi- valent to that of the reaction of diarylacetylene with Co_2(CO)_8. Conformational analysis has shown that R groups in complexes A are linked to sulfur atoms by a-and e-bond, whereas that in B only by art e-type of bond.

A DV-X_α study on the electronic structures of cubane-like iron-sulfur cluster compounds

The electronic structures of six cubane-like cluster compounds of the type[Fe_4S_4L_4]~n (L=SH,OH,and CI,n=-2 and -3;L=NO,n=0 and -1)have been calculated by using DV-X_α method,and the bonding properties are discussed with emphasis on the ligand effect on cluster bonding. The comparisons of MO energies and cluster charge distributions with the experimental data are made, and the differences between the early studies and the present one are also briefly commented.