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A two-dimensional (2D) arrangement of metallofullerenes for both M@C82 (isomer I) (M = Y, La, Ce, Pr) and (M2Cy)@C82 (isomer III) (M = Er, y = 0, 2; M = Sc, y = 2) is crystallized with a 1:2 fullerene/toluene molecular ratio. The determined crystal is a 2D layered structure, which is composed of metallofullerene layers sandwiched by the toluene layers. Although the M@C82(I) arrangement in a 1:1 crystal is almost identical to that of (M2Cy)@C82(III), the M@C82(I) arrangement in a 1:2 crystal is different from (M2Cy)@C82(III). It is found that the difference of the molecular arrangement strongly correlates with an orientation of metallofullerenes in a 2D layer. Our findings suggest the existence of a subtle but important interaction between the confined atoms/molecules and the solvent molecules/toluene through the carbon cage, which leads to a guiding principle of crystallization control with a solvent ingredient for metallofullerenes.

Food-additive grades of capsanthin, lutein, lycopene, and β-carotene dispersed in aqueous solutions were photo-irradiated using a Xenon weather meter, and the levels of carotenoids were measured by HPLC and the absorbance method. Capsanthin photo-degraded more rapidly than the carotenoids tested, with less oxygen consumption. Unlike carotenes, capsanthin was partially converted into analogous colored compounds during degradation.

Systematic structural studies of 24 different kinds of endohedral metallofullerenes, M(x)C(2n) (M = La, Y, Sc, Lu, Ti, Eu, Er, Hf, Sc(3)N; 34 ≤ n ≤ 43), as 1:1 cocrystals with solvent toluene molecules have been carried out using synchrotron radiation powder diffraction. Thirteen of the 24 molecular structures, including five metal carbides, one metal nitride endohedral fullerene, and one hollow fullerene, have been determined by a combination of the maximum entropy method and Rietveld refinement of the X-ray diffraction data obtained. We have found that the volume for one fullerene and one toluene molecule depends linearly on the number of carbon atoms in the fullerene cage. Fifteen different kinds of metal carbide endohedral fullerenes have been identified, which can be structurally characterized from the obtained lattice constants using only this linear dependence. The linear dependence found in the present study provides a metallofullerene diagnostics diagram that may have universal importance for structural characterization of the so-called cluster endohedral fullerenes.

The luminous efficiency of white light-emitting diodes, which are used as light sources for next-generation illumination, is continuously improving. Presently available white light-emitting diodes emit with extremely high luminance because their emission areas are much smaller than those of conventional light sources. Consequently, white light-emitting diodes produce a glare that is uncomfortable to the human eye. Here we report a yellow-emitting phosphor, the Eu(2+)-doped chlorometasilicate (Ca(1-x-y,)Sr(x,)Eu(y))(7)(SiO(3))(6)Cl(2), which can be used to create glareless white light-emitting diodes. The (Ca(1-x-y,)Sr(x,)Eu(y))(7)(SiO(3))(6)Cl(2) exhibits a large Stokes shift, efficiently converting violet excitation light to yellow luminescence, and phosphors based on this host material have much less blue absorption than other phosphors. We used crystal structure analysis to determine the origin of the desired luminescence, and we used (Ca(1-x-y,)Sr(x,)Eu(y))(7)(SiO(3))(6)Cl(2) and a blue-emitting phosphor in combination with a violet chip to fabricate glareless white light-emitting diodes that have large emission areas and are suitable for general illumination.

Various porous titania photocatalysts are analyzed three-dimensionally in real space by electron tomography. Shapes and three-dimensional (3D) distributions of fine pores and silver (Ag) particles (2 nm in diameter) within the pores are successfully reconstructed from the 3D data. Electron tomography is applied for measuring the specific surface area of the porous structures including open and closed porosity. Calculated specific surface areas of 22.8 m2/g for a conventional sol-gel TiO2 sample and 366 m2/g for a highly porous TiO2 sample prepared using the Pluronic P-123 self-assembly process are compared with those measured by the general BET method. The real-space surface measurement indicates that the highly porous TiO2 produced by the present method using block copolymers has a greater number of effective reaction sites for the degradation of methylene blue. Electron tomography shows a great potential to contribute considerably to the nanostructural analysis and design of such catalyst materials for photocatalysis.

Genetic Algorithm (GA) applied to ab initio structure determination from synchrotron powder diffraction is described. It seems to have an advantage over other real space methods for ab initio structure determination because of the existence of schema theorem. As an example, the case of Prednisolone Succinate is shown in some detail. Future development of GA in crystallography is briefly described.

金沢大学国際基幹教育院, We determine the crystal structure of the intermediate antiferroelectric (A2) phase of PbHfO3 by a Rietveld method using X-ray and neutron diffraction. The structure can be described by modulations associated with the lattice vibrational mode Σ3(TO) with q (0.15,0.15,0)and the Rxy 25 mode, although the latter modulation is relatively distorted. The size of the orthorhombic unit cell is p2 × 10p2 × 2 times as large as that of the high-temperature cubic cell. The space group is Pbam-D9 2h (No. 55), and is the same as that of the room-temperature antiferroelectric (A1) phase of PbHfO3. © 2018 Physical Society of Japan. All rights reserved., Embargo Period 12 months

An X-ray magnetic diffraction (XMD) is applied to ferromagnetic transition metal oxide YTiO3. The spin magnetic form factors are measured for 81 reciprocal lattice points of h0l, hk0 and 0kl series. Three-dimensional spin density distribution in the real space of YTiO3 is successfully obtained by using Maximum Entropy Method (MEM). This is the first result of spin density in the real space by the XMD.

The four-probe resistivity measurements were performed on the molecular crystals of TMTTeN (=tetramethyltetratelluronaphthalene) and [Ni(ptdt) 2 ] (ptdt=propylenedithio tetrathiafulvalenedithiolate) by using a diamond anvil cell (DAC) up to 30 and 21 GPa, respectively. In spite of extremely large enhancement of room-temperature conductivity (∼350 Scm −1 at 25.4 GPa) and metallic behavior at low temperatures (25–65 K at 25.4 GPa), the pressure-induced metallic state could not be observed in TMTTeN up to 30 GPa at least around room temperature. The resistivity of [Ni(ptdt) 2 ] decreased with increasing pressure and became approximately 10 −2 Ω cm at 18 Gpa. The temperature dependence of the resistivity exhibited a weakly semiconducting behavior. At around 19.5 GPa, [Ni(ptdt) 2 ] showed weakly metallic behavior down to low temperature. However, this pressure-induced metallic state was not stable. At 20.7 GPa, the resistivity increased again below 40 K. The four-probe resistance measurements were also performed on the extremely brittle thin-plate microcrystals of single-component antiferromagnetic molecular conductor [Au(tmdt) 2 ]. The resistance ( R ) decreased continuously with decreasing temperature ( T ). Except for a slight bending of the R−T curve at around the magnetic transition temperature ( T N =110 K), no resistance anomaly was observed. Nonetheless, the existence of the metallic state below T N was confirmed for the first time from the results of single-crystal resistance measurement. The precise crystal structure examinations were performed on [Au(tmdt) 2 ] by the powder X-ray diffraction data at the temperature range of 9–300 K.

Accurate structure factors are extracted from synchrotron powder diffraction data measured on crystalline diamond based on a novel multipole model division of overlapping reflection intensities. The approach limits the spherical-atom bias in structure factors extracted from overlapping powder data using conventional spherical-atom Rietveld refinement. The structure factors are subsequently used for multipole electron-density modelling, and both the structure factors and the derived density are compared with results from ab initio theoretical calculations. Overall, excellent agreement is obtained between experiment and theory, and the study therefore demonstrates that synchrotron powder diffraction can indeed provide accurate structure-factor values based on data measured in minutes with limited sample preparation. Thus, potential systematic errors such as extinction and twinning commonly encountered in single-crystal studies of small-unit-cell inorganic structures can be overcome with synchrotron powder diffraction. It is shown that the standard Hansen-Coppens multipole model is not flexible enough to fit the static theoretical structure factors, whereas fitting of thermally smeared structure factors has much lower residuals. If thermally smeared structure factors (experimental or theoretical) are fitted with a slightly wrong radial model (s2p2 instead of sp3) the radial scaling parameters (`' parameters) are found to be inadequate and the `error' is absorbed into the atomic displacement parameter. This directly exposes a correlation between electron density and thermal parameters even for a light atom such as carbon, and it also underlines that in organic systems proper deconvolution of thermal motion is important for obtaining correct static electron densities.

1-Ferrocenylethynylanthraquinone (1-FcAq), which is a donor (D)-acceptor (A) conjugated compound consisting of a ferrocene (Fc) acting as a donor, an anthraquinone (Aq) acting as an acceptor, and an ethynyl linker, undergoes a cyclocondensation reaction with strong organic acid, and forms 2-ferrocenyloxodihydrodibenzochromenylium salts ([1-FcPyl](+)X(-) where X = TFSI, TfO, PF(6), and BF(4)). [1-FcPyl](+) were also characterized as conjugated donor-acceptor compounds, and electrochemical properties, UV-vis absorption spectra, single-crystal X-ray analysis, and TD-DFT calculations have indicated that the LUMO level of [1-FcPyl](+) is lower than that of 1-FcAq because of the much larger pi-conjugated system in [1-FcPyl](+). Variable-temperature Mossbauer spectroscopy (12-300 K) showed that Fe(II) was dominant for the TFSI(-), PF(6)(-), and BF(4)(-) salts of [1-FcPyl](+); although the Fe(III) species was also observed at all temperature ranges, the molar ratio of Fe(III) species increased at higher temperatures in the TFSI(-) and PF(6)(-) salts. This finding indicates that valence tautomerization (VT) between 1-FcPyl(+) and 1-Fc(+)Pyl occurs in the solid state of the TFSI(-) and the PF(6)(-) salts, but not in the BF(4)(-) salt. Variable-temperature (3.5-310 K) IR spectroscopy showed that the frequencies of the skeletal vibration of the ferrocene moiety decreased with increasing temperature in the TFSI(-) and PF(6)(-) salts, indicating the development of a ferrocenium-like character. The precision of the bond lengths of the [1-FcPyl](+) moiety (0.003-0.004 A) determined by single-crystal X-ray analysis (113 and 273 K) is not sufficient to demonstrate the effect of the counterion on VT. The dihedral angle between the ferrocene and the pyrylium moieties in the BF(4)(-) salt (11.25(15) degrees) is larger than that in the TFSI(-) (6.63(12) degrees) and PF(6)(-) (9.55(15) degrees) salts. Furthermore, the planarity of the acceptor moiety (estimated from the dihedral angle between Ph1 and Ph2) is lower in the BF(4)(-) salt compared with that of other salts. These increased dihedral angles might cause a weaker D-A interaction and a destabilization of the acceptor moiety (i.e., raising a LUMO level), leading to lower stability of the Fe(III) (1-Fc(+)Pyl) species. Variable-temperature X-ray powder diffraction (VT XRPD, 100-300 K) revealed that the temperature dependence of the Fe-P distance in the PF(6)(-) salt was smaller than that of the Fe-B distance in the BF(4)(-) salt. Our interpretation of this phenomenon is that the molar ratio of the Fe(III) species is increased in the PF(6)(-) salt, and that the Coulombic force between the ferrocene moiety and PF(6)(-) anion increases, preventing an increase in the Fe-P distance. This indicates that the electrostatic interaction between the [1-FcPyl](+) moiety and the counteranion may affect the occurrence of VT.

The crystal structure of the single-component molecular metal [Au(tmdt)(2)] was examined at pressures up to 10.7 GPa in order to examine whether the high-pressure structure reflects the crystal's metallic nature. Crystal structure analyses were performed at 0.2, 0.8, 1.3, 3.0, 5.5, and 10.7 GPa on the basis of the powder X-ray diffraction data obtained by using the synchrotron radiation source SPring-8. The unit cell volume at 10.7 GPa was approximately 75% of the initial volume, indicating that [Au(tmdt)(2)] is a 'soft material' like a typical molecular crystal in spite of its metallic nature. The pressure dependences of the bond lengths of the Au(tmdt)(2) molecule were found to be approximately 1 order of magnitude smaller than those of the intermolecular atomic distances. These results seem to justify the commonly accepted conjecture that the molecule usually behaves almost like a rigid body up to a fairly high pressure. It was found that the anisotropy of the lattice compression of the insulating I(2) crystal below 20 GPa can be essentially interpreted on the basis of a very simple 'interatomic repulsion model', which assumes that the molecules in the crystal are packed such that as far as possible, an increase in the interatomic repulsions between neighboring molecules is avoided. However, the maximum decrease in the intermolecular distance in [Au(tmdt)(2)] was observed along the a direction although there were many intermolecular S...S contacts shorter than the van der Waals distance (3.70 A) along this direction. The shortest intermolecular S...S distance was 2.73 A at 10.7 GPa, which is approximately 1 A shorter than the S...S van der Waals distance (3.70 A). The crystal lattice of [Au(tmdt)(2)] is considered to be stabilized by the enhancement of the intermolecular overlapping of the conduction molecular orbitals having large amplitudes on peripheral S atoms. Although the crystal is composed of 'isolated molecules' like a typical insulating molecular crystal, its compressibility behavior seems to reflect its metallic nature.

Single-component molecular conductors [M(tmstfdt)2] (M = Ni, Au; tmstfdt = trimethylenediselenadithiafulvalenedithiolate) substituted with Se atoms are prepared and found to be isostructural with [M(tmdt)2] (M = Ni, Au; tmdt = trimethylenetetrathiafulvalenedithiolate). Measurements of the electrical conductivity and magnetic susceptibility of [Ni(tmstfdt)2] show that it has essentially metallic properties down to low temperatures. The resistivity measurements of [Au(tmstfdt)2] suggest it undergoes a metal-insulator phase transition at around 100 K. Magnetic susceptibility and ESR measurements of [Au(tmstfdt)2] indicate that it undergoes a magnetic transition at around 5 K, which is much lower than theantiferromagnetic (AF) phase-transition temperature of [Au(tmdt)2] (110 K). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

In situ high-temperature powder X-ray diffraction experiments have been performed on performed on Pb10.5Sb6Te57.9 using using a synchrotron X-ray source to observe the eutectoid reaction from Pb2Sb6Te11 to PbTe and Sb2Te3. Molar fractions of the constituent phases and fraction transformed were obtained as functions of time. The experimental fraction transformed vs. time curve were well fitted by the Kolmogorov–Johnson–Mehl–Avrami equation with an Avrami index n = 1.4. The small n value suggests that the growth of the new phases PbTe and Sb2Te3 is one-dimensional.

The structure of a pharmaceutical compound, prednisolone succinate, has been determined by a newly developed analytical method forab initiostructure determination and refinements from X-ray powder data. It consists of a genetic algorithm (GA) for the structure determination process and the maximum entropy method (MEM), including its variations, for the structure refinement process. The crystal structure of prednisolone succinate has two molecules in the asymmetric unit and the total number of degrees of freedom is 25. In the structure refinement process, the various kinds of MEM analyses, such as difference MEM and omit MEM, in addition to ordinary MEM, play crucial roles in obtaining a better structural model. The data used in the present study were collected at BL02B2, SPring-8, which allowed the use of a wided-spacing range,d> 1.0 Å. The reliability factors,RwpandRI, of the final structure analysis by Rietveld refinement are less than 0.013 and 0.048, respectively. The structure determined in the present study gives noCHECKCIFalert relating to the fundamental structure, such as interatomic distances and bond angles, even in chemical bonds involving H atoms.

The capability of powder diffraction has greatly increased in X-ray diffraction field since the advent of synchrotron light source, particularly third generation synchrotron source, such as SPring-8. In neutron field, J-PARC is about to start. This means we will have advanced powder diffraction instruments in both X-ray and neutron diffraction fields. The capability of powder diffraction is surely affected by the method used in data analysis. The most common analytical method is Rietveld refinement. Recently, the sophisticated analytical method called MEM/Rietveld, become powerful tool to extract the structural information included in the accurately measured experimental data. In this article, possibilities of powder diffraction utilizing advanced neutron source, i.e. J-PARC and/or advanced neutron and X-ray sources simultaneously, will be described bearing in mind that improvement of the advanced analytical method would occur.

The thermoelectric material Zn4Sb3 was mercury doped by introduction of 1 at. % Hg into the synthesis mixture, resulting in Hg0.04Zn3.96Sb3. The doped compound and an undoped reference were characterized by multitemperature short wavelength synchrotron X-ray powder diffraction, SEM/EDX, differential scanning calorimetry (DSC), and physical property measurements. Rietveld refinements suggest that mercury substitution takes place solely on the Zn1 framework site of the disordered room temperature β-phase crystal structure, while the interstitial positions are mercury-free. The refined composition suggests a doping level of 0.6%. The remaining mercury is present as elemental Hg as evidenced by SEM/EDX analysis, the presence of peaks corresponding to crystalline Hg below the Hg freezing temperature, and the presence of a drop in the resistivity at the superconducting transition temperature of Hg. Rietveld refinements of multitemperature synchrotron X-ray powder diffraction data (180 K < T < 290 K, ΔT = 10 K) ...

The instability of some industrially important synthetic azo colorants, including sunset yellow, azorubine, and allura red, toward gum arabic in aqueous solution has been a long-standing problem for the beverage and confectionery industries. Precipitation of these colorants causes the deterioration of product appearance and properties. This work examines the origin and nature of the problem by analysis of the precipitate and thermodynamic studies of gum arabic-colorant interactions using isothermal titration calorimetry (ITC). The presence of divalent alkaline earth metals in gum arabic samples, that is, calcium and magnesium, is shown to be responsible for the precipitation of the azo colorants. There is no direct interaction between gum arabic and the colorant molecules, and the precipitate is formed likely due to the mediation/bridging by the divalent cations. The thermodynamic knowledge gained from the ITC studies, for example, binding affinity, stoichiometry, and enthalpy, enables interpretation of many industrial observations.

Double-wall carbon nanotubes (DWNTs) encapsulating C 60 and C 70 fullerenes have been synthesized by the vapor reaction method. Arrangements of C 60 and C 70 molecules in phases of single chain and multi-layers are observed in DWNTs of different sizes by TEM observation. Distinct signals of XRD patterns and Raman spectra can distinguish C 60 and C 70 fullerenes inside from those attached outside DWNTs. TGA of the as-prepared DWNT-peapods clearly show that they have a higher thermal stability in comparison with pristine DWNTs. This supplies a simple method to evaluate the filling ratio of peapods, which is 74.7 wt% for the current DWNT-peapods.

Accurate structure factors of silicon and diamond have been experimentally determined from powder diffraction data measured at the third-generation synchrotron-radiation source SPring-8, BL02B2. The accuracy of the obtained structure factors has been evaluated by comparing with structure factors in the literature measured by the Pendellösung method and with some from theoretical calculations. The results indicate that the structure factors from powder data are accurate enough to discuss the experimental charge-density distributions of these materials. The number of structure factors of silicon determined in the present study is 104, which is three times more than that of previous Pendellösung data. The experimental charge densities have been obtained by the maximum-entropy method from the present structure factors. The charge densities at bond mid-points for silicon and diamond show good agreement with different kinds of theoretical calculations. The present study proved that the powder diffraction at SPring-8 is a promising method for determination of experimental charge density for a wider range of materials.

A systematic powder X-ray structure study for (Sc2C2)@C82(isomer III) and (Y2C2)@C82(III) is carried out by the MEM/Rietveld method by using high resolution synchrotron radiation powder data. In both fullerene materials, two carbon atoms are encapsulated in the cage and a M2C2 bent cluster is most likely formed in the cage. The obtained cage structure of Sc2C84(III) is C82–C3V(8), which is the same as those of (Y2C2)@C82(III) and Y2@C82(III). The charge density of C2 is located at the center of fullerene cage. Two scandium atoms show the rotational disorder, indicating the presence of a rapid hopping motion inside C82–C3V(8) cage. The inter-atomic distances between metal and carbon atoms on fullerene cage are 2.29 A for (Sc2C2)@C82(III), which is 0.2 A smaller than that of (Y2C2)@C82(III).

A new hybrid material C10H2@SWNTs, single-wall carbon nanotubes (SWNTs) encapsulating C10H2 polyyne molecules, has been synthesized and confirmed by Raman spectroscopy and X-ray diffraction measurement. The C10H2 polyyne molecules composed of linearly bonded sp-carbon atoms are aligned inside the SWNTs. This hybrid material exhibits a characteristic Raman signal at 2066 cm−1 attributable to the stretching vibration of the C10H2 molecules interacting with SWNTs. Being trapped inside the SWNTs, the otherwise unstable C10H2 molecules are shown to be stable well above 300 °C under dry-air conditions.

The spin-crossover complex [Fe(teec)(6)](ClO(4))(2) (teec = chloroethyltetrazole) exhibits a 50 % incomplete spin crossover in the temperature range 300-30 K. Time-resolved synchrotron powder diffraction experiments have been carried out to elucidate its structural behavior. We report crystal structure models of this material at 300 K (high spin) and 90 K (low spin), as solved from synchrotron powder diffraction data by using Genetic Algorithm and Parallel Tempering techniques and refined with Rietveld refinement. During short synchrotron powder diffraction experiments (five minutes duration) two distinguishable lattices were observed the quantities of which vary with temperature. The implication of this phenomenon, that is interpreted as a structural phase transition associated with the high-to-low spin crossover, and the structural characteristics of the high-spin and low-spin models are discussed in relation to other compounds showing a similar type of spin-crossover behavior.

The prolyl aminopeptidase complexes of Ala-TBODA [2-alanyl-5- tert -butyl-(1, 3, 4)-oxadiazole] and Sar-TBODA [2-sarcosyl-5- tert -butyl-(1, 3, 4)-oxadiazole] were analyzed by X-ray crystallography at 2.4 Å resolution. Frames of alanine and sarcosine residues were well superimposed on each other in the pyrrolidine ring of proline residue, suggesting that Ala and Sar are recognized as parts of this ring of proline residue by the presence of a hydrophobic proline pocket at the active site. Interestingly, there was an unusual extra space at the bottom of the hydrophobic pocket where proline residue is fixed in the prolyl aminopeptidase. Moreover, 4-acetyloxyproline-βNA (4-acetyloxyproline β-naphthylamide) was a better substrate than Pro-βNA. Computer docking simulation well supports the idea that the 4-acetyloxyl group of the substrate fitted into that space. Alanine scanning mutagenesis of Phe139, Tyr149, Tyr150, Phe236, and Cys271, consisting of the hydrophobic pocket, revealed that all of these five residues are involved significantly in the formation of the hydrophobic proline pocket for the substrate. Tyr149 and Cys271 may be important for the extra space and may orient the acetyl derivative of hydroxyproline to a preferable position for hydrolysis. These findings imply that the efficient degradation of collagen fragment may be achieved through an acetylation process by the bacteria.

We have performed magnetic susceptibility measurements and precise crystal structure analysis of the nonstoichiometric NbB2+x superconductor to reveal the relationship between Tc and crystal structure. From magnetic susceptibility measurements, it was found that Tc increases from 2.2 to 5.8 K with x. The crystal structures including both chemical compositions and lattice constants were precisely determined by Rietveld refinement using synchrotron X-ray powder diffraction data with three different wavelengths. We found that interatomic Nb–B distance increases with Tc. The charge density of NbB2+x was revealed by the maximum entropy method based on Rietveld refinement. We find the difference in the number of electrons in the Nb site and B layer for NbB2+xwith different compositions and Tc.

An EMI-based room-temperature (RT) ionic liquid containing d5 trivalent iron(III) ions [EMI][FeIIICl4] was fully investigated, where EMI is 1-ethyl-3-methylimidazolium. The viscosity of the salt is...

We present structures of PbHfO 3 between 100 and 525 K analyzed by a Rietveld method using synchrotron radiation. Spontaneous strain of a perovskite sublattice could be excellently expressed by a c...

The charge density distribution of Nd 0.35 Sr 0.65 MnO 3 has been investigated by means of the maximum entropy method (MEM) using the synchrotron radiation (SR) X-ray powder diffraction data. In this compound, the anisotropic optical spectra reported by Tobe et al. [Phys. Rev. B 67 (2003) 140402(R)] suggest that the d 3 z 2 - r 2 orbital-ordering survives even at 600 K (≫ T N = 260 K). Consistently, we observed an anisotropic charge density distribution around the Mn ion at 30 K (≪ T N ), indicating the long-range ordering of the d 3 z 2 - r 2 orbital. At 300 K (≥ T N ), however, the charge density distribution becomes isotropic, suggesting the disappearance of the long-range orbital ordering.

Temperature-dependent X-ray diffraction (XRD) studies using synchrotron radiation and Raman spectral studies in the range of 40–850 cm−1 have been carried out for crystalline polymorphs of the titl...

The experimental and analytical method of the high-pressure powder experiment at BL10XU, SPring-8, is described. There is no doubt that BL10XU must be one of the most appropriate beam lines for high pressure X-ray diffraction experiment taking advantage of third generation synchrotron source. As an example of the advanced charge density study under high pressure, the structural change of Cs 2 Au 2 Br 6 by applying pressure is studied by Rietveld/MEM analysis. It reveals that the structural change of Cs 2 Au 2 Br 6 by applying pressure occurs basically at electron level, such as valence state change and chemical bonding, which may be called the electronic phase transition.

The novel nickel complex with the extended-TTF dithiolate ligand [Ni(tmdt) 2 ] (tmdt=trimethylene dithiotetrathiafulvalenedithiolate) is the first three-dimensional single-component molecular metal with metallic state down to very low temperature (0.6 K). Recently, the direct evidence for presence of electron and hole Fermi surfaces in [Ni(tmdt)2] was obtained by detecting the de Haars-van Alphen (dHvA) effect. We have synthesized analogous single-component molecular conductors with various ligands and central metal atoms and examined their structures and physical properties. The visible and ir spectra of single-component molecular conductors showed that these molecules have unprecedentedly small HOMO-LUMO gaps.

A structure analysis of Zn-Mg-Ho icosahedral quasicrystal was carried out by the powder X-ray diffraction method using synchrotron radiation (Lambda=0.73490 A) at SPring-8. The intensity distribution was analyzed by the Rietveld method modified for an icosahedral quasicrystal, in which simplified models were assumed: ellipsoid and spherical windows were assumed at five crystallographic sites in a F-type hypercubic unit cell. The analysis revealed the presence of an almost perfect Penrose tiling with edge length 5.20 A. The vertices are occupied alternatively by Zn and Mg, and almost all of the edge centers of the Penrose rhombohedra are occupied by 0.8Zn and 0.2Mg. Ho and Mg atoms tend to be present on the body diagonal of the prolate rhombohedra. Good agreement between the measured and calculated intensity distribution using the simplified model suggests the applicability and the limitation of structure analysis using the powder X-ray diffraction method., 10 pages, 3 tables, 3 figures

The drying process of the rinse water affects strongly to pattern collapse phenomena during development process. In order to analyze the water meniscus behavior, a PET film is used as a parallel line pattern. By using this transparent pattern, wetting behavior of water meniscus between two patterns can be observed. In the drying process of water meniscus, it is clearly observed that the meniscus enters from the side edge of the parallel pattern. The meniscus behavior can be analyzed based on capillary rise and gravity.

Crystal structure determination and analysis have been carried out for the two spin-crossover compounds [Fe(teeX)6](BF4)2 (teeX is haloethyltetrazole; X = I: teei; X = Br: teeb), in both their high-spin (near 300 K) and their low-spin states (T = 90 K), using high-resolution powder-diffraction data collected at the ESRF (Grenoble, France) and SPring8 (Japan) synchrotron radiation facilities. The structures of teei have been solved using various direct-space structure determination techniques (grid search, genetic algorithm and parallel tempering) and refined with the Rietveld method using geometrical restraints. In the case of teeb, a structural model was found but a full refinement was not successful because of the presence of a significant amount of an amorphous component. Analysis of the structures (space group P21/c, Z = 2) and diffraction data, and the absence of phase transitions, show the overall structural similarity of these compounds and lead to the conclusion that the gradual spin-crossovers are likely to be accompanied by small structural changes only.

The measurements of electrical resistivity, magnetic susceptibility, specific heat, thermopower and powder x-ray diffraction under pressure have been performed on single crystals of Y 1- x Ca x TiO...

We have investigated the structural properties of the photo-induced metastable phase of a Prussian blue analogue (Na 0.42 Co[Fe(CN) 6 ] 0.78 ·4.64H 2 O), which shows the photo-magnetization phenomenon, as revealed by means of the high angle-resolved synchrotron-radiation X-ray powder diffraction technique. We have found that (1) the structural domain size is larger than the quenched high-temperature phase and (2) the lattice constant a (=10.287(1) A) is larger than that of the quenched phase ( a =10.187(3) A). These observations indicate that photo-excitation coherently increases the size of the photo-induced metastable region even at low temperature (91 K≪ T c ).

The structure of an IPR-violated metallofullerene Sc2@C66 has been determined in the electron density level by the MEM/Rietveld method using synchrotron radiation powder data. The fundamental structure has been obtained by the Rietveld analysis. The cage structure of C66 has been unambiguously identified as that of Isomer No. 4348. The obtained charge density by the MEM analysis shows that the encapsulated two Sc atoms form the covalent bonded Sc2 dimer and that the charge density of dimer is overlapping with that of C66 cage, indicating the existence of a covalent bond character between Sc2 and the carbon cage.

We report the structural study of C 70 -one-dimensional (1D) crystal formed inside single-walled carbon nanotubes (SWNTs). X-ray diffraction measurements were performed between 100 K and 999 K on C...

The recent progress of the structural studies of endohedral metallofullerenes by the synchrotron radiation (SR) powder diffraction utilizing the maximum entropy method (MEM) is reviewed. Results of the endohedral metallofullerenes (Y@C82, La@C82, Sc@C82, Sc2@C84, Sc3@C82, Sc2@C66, La2@C80 and Sc2C2@C84) are given. The precise MEM charge densities of metallofullerenes presents the direct image of endohedral nature of metallofullerenes indicating the charge transfer from metal atoms to carbon cage, which governs the stability of the unique endohedral structures. The MEM/Rietveld method and SR powder method using imaging plate (IP), which are the crucial methods for data analysis and measurement in order to determine structure of fulleride, are also mentioned in some detail.

We have performed in situ synchrotron-radiation X-ray powder structural analysis in a spin-crossover complex ([Fe(ptz) 6 )](BF 4 ) 2 : ptz = propyltetrazole) under a photo-excitation with a continuous-wave (CW) green (532 nm) laser at 91 K. The Fe 2+ ions in the Fe(ptz) 6 molecules take the low-spin (LS: S = 0) state at the ground state, and are photo-excited selectively into the high-spin (HS: S = 2) state. When the excitation power P exceeds the critical value, we observed a novel secondary phase which can be ascribed to the condensation of the photo-excited HS ions.