Synchrotron radiation studies of the orientation of thin silicon phthalocyanine dichloride film on HOPG substrate

Thin silicon Phthalocyanine dichloride films on HOPG were prepared and the sample was heated in the vacuum with laser.The thickness of the thin sample on HOPG was checked by X-ray photoemission spectroscopy.The orientation of the molecules in respect to the substrate plane Was investigated by measuring the silicon K-edge near edge X-ray absorption fine structure(NEXAFS).In the NEXAFS spectra of the thin sample,two clear peaks which were assigned to 1s→σ*Si-N and 1s→σ*Si-C1 appeared around 1847.2 eV and 1843.1 eV respectively.The intensities of the resonance peaks showed strong polarization dependence.A quantitative analysis of the polarization dependence revealed that the Si-N bond tended to lie down while the Si-C1 bond was out of the molecular plane.     

Study on selective adsorption of deuterium on boron nitride using photon-stimulated ion-desorption

Adsorption behavior of atomic deuterium on a hexagonal boron nitride (h-BN) thin film is studied by photon-stimulated ion desorption (PSID) of D⁺ and near edge X-ray absorption fine structure (NEXAFS) at the B and N K-edges. After the adsorption of atomic deuterium, D⁺ desorption yield η(hν) shows clear enhancement at the B K-edge and almost no enhancement at the N K-edge. NEXAFS spectra show a large change in the B K-edge and a small change in the N K-edge after the adsorption. We propose selective adsorption of atomic deuterium on the h-BN thin film based on the experimental results, and mention the effectiveness of applying the PSID method with X-ray to study hydrogen storage materials.     

Synthesis and adsorptivity of acryloylmorpholine resin to various fission product elements in nitric acid media

A novel silica-supported resin with a cyclic monoamide of polymerized 4-acryloylmorpholine(Silica-AM) was synthesized, and adsorptivity to metal ions of major fission products(FP) was examined in HNO3 and HCl solutions. Silica-AM has a carbonyl oxygen atom outside of the 6-membered morpholine ring, and a cyclic structure that is different than other cyclic monoamide resins we have studied. These include polyvinylpolypyrrolidone(PVPP) and poly-N-vinyl-ε-caprolactam(VEC), both of which have coordinative carbonyl groups included in the ring. Silica-AM was similar to a cyclic monoamide we have reported because it exhibited adsorption to Pd(Ⅱ) and Re(VⅡ) in HNO3 of a particularly low concentration range. Silica-AM has an ether oxygen atom included in the ring as well. Considering the difference in the chemical structures of Silica-AM and other cyclic monoamide resins, it was suggested that oxygen atoms in the carbonyl group and in ether may be main contributors to Silica-AM's respective adsorptions to Pd(Ⅱ) and Re(VⅡ), and Mo(VI) and Zr(IV). Our results imply that the contribution of the two types of oxygen atoms to adsorption is more observable in an HCl system. The contribution of the ether oxygen atom to the adsorption of Pd(Ⅱ) was also suggested from our study on crystal prepared from 4-acetylmorpholine and palladium nitrate.     

High-pressure synthesis, crystal and electronic structures, and transport properties of a novel perovskite HgSnO3

We synthesized a novel perovskite-type oxide, HgSnO3, under high pressure and high temperature, and investigated the crystal and electronic structures as well as the transport properties. It was found that HgSnO3 possesses a trigonal-hexagonal lattice with space group R3c. The band gap of HgSnO3 estimated by diffuse reflectance spectrum measurement is relatively small (1.6 eV), irrespective of the large octahedral tilting distortion. The small band gap is caused by the increase in the bandwidth of the conduction and valence bands due to mixing between the empty Hg 6s orbitals and the antibonding Sn 5s-O 2p states and the mixing between the filled Hg 5d orbitals and the O 2p states, respectively. The electronic resistivity, Seebeck coefficient, and Hall coefficient measurements indicate that as-synthesized HgSnO3 is an n-type semiconductor.     

Two-color laser manipulation of single organic molecules based on nonlinear optical response

We theoretically propose two-color laser manipulation with greatly improved efficiency to mechanically manipulate single organic molecules. The present method is based on the nonlinear resonant laser manipulation proposed in a recent study. In the first part, we describe a method to trap single organic molecules that can be more effective than ever before utilizing two-color beams. In the second part, we demonstrate the possibility to selectively “pull” single organic molecules with a particular type of electronic-level scheme by using single-side illumination of traveling light.     

High-pressure synthesis and correlation between structure, magnetic, and dielectric properties in LiNbO(3)-type MnMO3 (M=Ti, Sn)

LiNbO(3)-type MnMO(3) (M = Ti, Sn) were synthesized under high pressure and temperature; their structures and magnetic, dielectric, and thermal properties were investigated; and their relationships were discussed. Optical second harmonic generation and synchrotron powder X-ray diffraction measurements revealed that both of the compounds possess a polar LiNbO(3)-type structure at room temperature. Weak ferromagnetism due to canted antiferromagnetic interaction was observed at 25 and 50 K for MnTiO(3) and MnSnO(3), respectively. Anomalies in the dielectric permittivity were observed at the weak ferromagnetic transition temperature for both the compounds, indicating the correlation between magnetic and dielectric properties. These results indicate that LiNbO(3)-type compounds with magnetic cations are new candidates for multiferroic materials.     

Selective adsorption of atomic hydrogen on a h-BN thin film

The adsorption of atomic hydrogen on hexagonal boron nitride (h-BN) is studied using two element-specific spectroscopies, i.e., near-edge x-ray absorption fine structure (NEXAFS) spectroscopy and x-ray photoelectron spectroscopy (XPS). B K-edge NEXAFS spectra show a clear change in the energy region of the π* band before and after reaction with atomic deuterium. On the other hand, N K-edge NEXAFS spectra show only a little change. B 1s XPS spectra show a distinct component at the low binding energy side of a main component, while N 1s XPS spectra show peak broadening at the high binding energy side. These experimental results are analyzed by the discrete variational Xα method with a core-hole effect and are explained by a model in which hydrogen atoms are preferentially adsorbed on the B sites of h-BN. Based on the experimental and theoretical results, we propose a site-selective property of BN material on adsorption of atomic hydrogen.     

Synchrotron radiation studies of the orientation of thin silicon phthalocyanine dichloride film on HOPG substrate

Thin silicon phthalocyanine dichloride films on HOPG were prepared and the     

Catalytic asymmetric epoxidation of alpha,beta-unsaturated amides: efficient synthesis of beta-aryl alpha-hydroxy amides using a one-pot tandem catalytic asymmetric epoxidation-Pd-catalyzed epoxide opening process

The catalytic asymmetric epoxidation of alpha,beta-unsaturated amides using Sm-BINOL-Ph3As=O complex was succeeded. Using 5-10 mol % of the asymmetric catalyst, a variety of amides were epoxidized efficiently, yielding the corresponding alpha,beta-epoxy amides in up to 99% yield and in more than 99% ee. Moreover, the novel one-pot tandem process, one-pot tandem catalytic asymmetric epoxidation-Pd-catalyzed epoxide opening process, was developed. This method was successfully utilized for the efficient synthesis of beta-aryl alpha-hydroxy amides, including beta-aryllactyl-leucine methyl esters. Interestingly, it was found that beneficial modifications on the Pd catalyst were achieved by the constituents of the first epoxidation, producing a more suitable catalyst for the Pd-catalyzed epoxide opening reaction in terms of chemoselectivity.