The possibility of modulating the electronic configurations of the innermost atoms inside a nanospace, nano sheath with chemical modification was investigated using synchrotron X-ray photoelectron spectroscopy. Systems of definite nanostructures were chosen for this study. Systematic variations in energy, intensity, and width of pi and sigma O 1s core level spectra, in absorption characteristics of C 1s-->pi transition, in photoabsorption of pre-edge and resonance regions of the Gd 4d-->4f transition, were observed for Gd@C(82) (an isolated nanospace for Gd), Gd@C(82)(OH)(12) (a modified nanospace for Gd), and Gd@C(82)(OH)(22) (a differently modified nanospace for Gd), and the reference materials Gd-DTPA (a semi-closed space for Gd) and Gd(2)O(3). A sandwich-type electronic interaction along [outer modification group]-[nano sheaths]-[inner metallic atom] was observed in the molecules of modifications. This makes it possible to control electron-donation directions, either from the innermost metallic atom toward the outer nano sheaths or the reverse. The results suggest that one may effectively tune the fine structures of electronic configurations of such a metallic atom being astricted into nanostructures through changing the number or category of outer groups of chemical modifications. This may open a door to realizing the desired designs for electronic and magnetic properties of functionalized nanomaterials.

Endohedral metallofullerenes (fullerenes with metal atom(s) encapsulated), as a novel form of carbon-related materials, [1] have attracted special attention for their potential applications [2][3][4][5][6][7][8][9][10] in electronic devices, [2,3] biomedical fields such as therapeutic medicine, [4,5] and a new generation of magnetic resonance imaging (MRI) contrast agents, [6][7][8] etc.Recently, the polyhydroxylated Gd@C 82 material was found to possess a very high efficiency of inhibiting cancer growth in vivo, and to have a strong capacity to improve immunity and interfere with tumor invasion in normal muscle cells. Unlike conventional anticancer chemicals that use a high toxicity to kill cells, this material shows non-toxicity in vivo and in vitro and does not kill normal cells directly. [9,10] This finding indicates that this type of material with proper surface modifications may realize the human dream of cancer chemotherapeutics of high efficacy but low toxicity. Although the structural and electronic properties of endohedral metallofullerenes have been well investigated, [1] the chemical functionalization of the metallofullerene and its properties are not yet well studied and understood. [11,12] Recently, a unique electronic structure of Gd@C 82 caused by the encapsulation of the Gd atom was theoretically predicted.[13]How do the electronic properties of the material vary if the C 82 nanostructure is further modified with chemical groups? This is an intriguing topic for exploring the functions of a new nanomaterial because the modulation of the electronic properties of metallic atoms restricted to a nanospace is of significant and wide interest, though it is especially difficult. Recently, it was found that electronic configurations of atoms inside the fullerene cage can be tuned via chemical modifications to the cage surface. [14] But, on the chemical modifications of metallofullerenes it was found theoretically that i) the highest occupied molecular orbital (HOMO) in M@C 82 tends to distribute locally, [13] ii) the addition locations prefer to initiate at the cage surface opposite to the metallic position, [15] and iii) the addition pattern on the hollow fullerene cage tends to array as a cluster which shifts with the increasing number of added groups.[16] These raise many intriguing questions, for example, how do the electronic properties of the modified material vary with the changing number of added groups to the outer surface? To this end, we synthesized and purified the Gd@C 82 and Gd@C 82 (OH) x materials with a changing number of hydroxyls. The electronic properties of the Gd@C 82 (OH) x film were then studied using synchrotron radiation photoemission spectroscopy (SRPES) and X-ray absorption spectroscopy (SRXAS). Surprisingly, when the OH groups reach a certain number in Gd@C 82 (OH) x , the electron emission of the innermost Gd shows a periodical emergence or disappearance, depending on how many hydroxyls are added to the outer surface of the fullerene cages. Such a unique phenomenon is observe...

Ce(3+) ions are introduced into the lattice of Y2Mo3O12 with a sol-gel method with the aim to reduce its hygroscopicity and pursue the interaction of crystal water molecules with the building block. It is found that Ce(3+) ions occupy the positions of Y(3+) in the lattice and have the function of expelling crystal water molecules in the microchannels so that the number of crystal water molecules decreases significantly as the Ce(3+) content increases and a complete depletion of the crystal water is achieved when the content of Ce(3+) is higher than 8 mol%. Based on the binding energy changes of Mo 3d and Y 3d with and without Ce(3+) in the lattice, the configuration of the crystal water in the building block is deduced, namely, a crystal water serves as a spring with its O(2-) pointing to the Y(3+) in an octahedron and with its H(+) approaching the next nearest O(2-) in the Y-O-Mo bridge. With such a configuration, the effects of the crystal water on the thermal expansion properties of Y2Mo3O12 and the like are explained. It is also shown that the number of crystal water molecules per molecular formula can be quantified by the full width at half maximum of the Raman bands or relative intensity with linear relationships, suggesting that Raman spectroscopy can be a potential tool in quantifying crystal water molecules at room temperature in this or related materials.

HfMgMo 3−x W x O 12 with x = 0.5, 1.0, 1.5, 2.0, and 2.5 are developed with a simple solid state method. With increasing the content of W, solid solutions of HfMgMo 3−x W x O 12 crystallize in an orthorhombic structure for x ≤ 2.0 and a monoclinic structure for x > 2.0. A near-zero thermal expansion (ZTE) is realized for HfMgMo 2.5 W 0.5 O 12 and negative coefficients of thermal expansion (NCTE) are achieved for other compositions with different values. The ZTE and variation of NCTE are attributed to the difference in electronegativity between W and Mo and incorporation of a different amount of W, which cause variable distortion of the octahedra and softening of the MoO 4 tetrahedra, and hence an enhanced NCTE in the aand c-axis and reduced CTE in the b-axis as revealed by Raman spectroscopy and x-ray diffraction.

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The optical properties of asymmetric ring structures are investigated theoretically by using the discrete dipole approximation method. The numerical results revealed that this kind of structure can achieve a giant localized field enhancement (LFE, 264) and a high LSPR sensitivity (corresponding FOM, 8.28) in the visible spectrum by Fano resonance, whose origin is discussed based on plasmon hybridization theory. Furthermore, the dependence of the Fano resonance on the polarization states of the incident light is also demonstrated. Giant LFE and high LSPR sensitivity enable this structure to be promising for surface enhanced Raman spectroscopy and sensing applications.

This research demonstrated that introducing amorphous NiO electrocatalysts onto the surface of ZnO photoanodes can effectively facilitate their PEC performance.

Abstract. This study evaluated the relationship between the productivity of aboveground coarse woody biomass and species richness at individual species and community levels in two large and fully stemmapped temperate forest plots in northeastern China. Although productivity-diversity relationships (PDRs) have been investigated for different forest ecosystems, specific patterns have rarely been documented for individual species. In our study, the PDR patterns were found to be scale dependent at the community level in both research forests. Productivity is positively linked with species richness at the 20 × 20 m sampling scale. At the 40 × 40 m scale, however, significantly positive PDRs were only observed in the mature forest. A summary statistic combining both productivity and richness characteristics was used to investigate whether and at which spatial scale individual species show positive, negative, or neutral PDRs. The results show that 66.7% of all focal species exhibited positive or negative PDRs in the near-mature forest, while 64.3% exhibited positive or negative PDRs in the mature forest. Contrary to expectations, there were few species showing positive PDRs in either forest. PDR patterns were found to be scale dependent in both forest types: Negative PDRs dominate at close neighborhoods in the nearmature forest, while both positive and negative PDRs were found in the mature forest. To our knowledge, this is the first analysis that evaluates the PDRs of individual species based on facilitative and competitive effects in their neighborhoods.