Photoproduction of Λ(1405) and Σ0(1385) on the Proton at {{\rm E}_{\gamma}} = 1.5–3.0 GeV at SPring-8/LEPS

The missing mass spectra of ${\gamma p \rightarrow K^{+}X}$ for ${\gamma p \rightarrow K^{+} n \pi^{+}\pi^{-}}$ reaction were measured to obtain the spectrum of Λ(1405). The spectra were measured for two charged decay modes of Λ(1405) separately and they were combined to cancel the effect of interference between the isospin 0 and 1 terms of the Σπ scattering amplitudes. Our goal is to obtain the differential cross section of Λ(1405) and Σ⁰(1385) photoproduction. The preliminary results are presented here.     

Development and certification of the new NIES CRM 28: urban aerosols for the determination of multielements

A new environmental certified reference material (CRM) for the determination of multielements in aerosol particulate matter has been developed and certified by the National Institute for Environmental Studies (NIES), Japan, based on analyses by a network of laboratories using a wide range of methods. The origin of the material was atmospheric particulate matter collected on filters in a central ventilating system in a building in Beijing city centre. The homogeneity and stability of this material were sufficient for its use as a reference material. Values for elemental mass fractions in the material were statistically determined based on the analytical results of the participating laboratories. Eighteen certified values and 14 reference values were obtained. The diameters, obtained from a micrographic image using image analysis software, of 99% of the particles were less than 10 μm, demonstrating that almost all the particles in the material could be classified as particles of 10 μm or less in aerodynamic diameter. The chemical composition and particle size distribution of this material were close to those of an authentic aerosol collected in Beijing. NIES CRM 28 is appropriate for use in analytical quality control and in the evaluation of methods used in the analysis of aerosols, particularly those collected in urban environments in northeast Asia Figure New NIES CRM 28 Urban Aerosols and photo micrograph of the material     

Dilatometric studies of reaction volumes for the formation of metal complexes in several solvents

A convenient technique is described to determine reaction volumes by means of direct dilatometry. Reaction volumes were determined for the following complexation reactions: formation of monoamminenickel(II) in water (–0.1±0.5 cm³-mol^–1); formation of the 1:1 nickel(II) complex with isoquinoline in methanol and ethanol (3.2±0.1 and 1.1±0.1 cm³-mol^–1, respectively); formation of the 1:1 isothiocyanatoiron(III) complex in water, Me₂SO, and DMF (8.9±0.2, 12.4±0.7, and 25.1±0.3 cm³-mol^–1, respectively); formation of the 18-crown-6 potassium complex in water (10.9±0.2 cm³-mol^–1). We discussed these values in terms of electrostriction and molecular size.     

Accurate LC-MS analyses for microcystins using per-15N-labeled microcystins

Per-¹⁵N-labeled microcystins were prepared for use as surrogates for accurate liquid chromatography–mass spectrometry analysis. Two strains of Microcystis aeruginosa were cultured in ¹⁵NO₃-containing TS-15 medium. To change from the incorporation of ¹⁴N to ¹⁵N into all cell components, cells of Microcystis aeruginosa were precultured in Na¹⁵NO₃-containing medium for more than 6 months. After mass cultivation of the strains, cells of each strain were harvested and lyophilized. Microcystin variants were extracted from the lyophilized cells and per-¹⁵N-labeled microcystin variants were purified using high-performance liquid chromatography and high-performance thin-layer chromatography. The structures of per-¹⁵N-labeled microcystin variants were confirmed by their mass spectrometry spectra and NMR spectra. When per-¹⁵N-labeled microcystins were used as surrogates for quantitative analysis of these toxins in cyanobacterial cells, excellent accuracy (98–106%) was obtained, with the m/z of M⁺, [M+1]⁺, and [M+2]⁺ of both microcystins and the per-¹⁵N-labeled microcystins as surrogates being completely separated. In conclusion, per-¹⁵N-labeled microcystins are excellent surrogates for microcystin analysis using liquid chromatography–mass spectrometry.     

Theoretical studies of phosphorescence spectra of tris(2,2'-bipyridine) transition metal compounds

Phosphorescence spectra of tris(2,2'-bipyridine) metal compounds, [M(bpy)3]n+, where M = Zn(II), Ru(II), Os(II), Rh(III), and Ir(III), were calculated using a harmonic oscillator approximation of adiabatic potential surfaces obtained by density functional theory (DFT). Using the Huang-Rhys (S) factors calculated by theoretical Franck-Condon analysis of T1 and S0 geometries, we successfully reproduced the emission spectra observed under various conditions by nonempirical calculations. The simulations of well-structured spectra of the Zn(II), Rh(III), and Ir(III) compounds confirmed that the emission originated from localized ligand-centered excited states with considerably distorted geometries of C2 symmetry. The spectrum simulation revealed that the phosphorescence state of [Ru(bpy)3]2+ was localized 3MLCT both in a solution and a glass matrix. Furthermore, a highly resolved phosphorescence spectrum observed for [Ru(bpy)3]2+ doped in a [Zn(bpy)3](ClO4)2 crystal was reproduced well using the geometry of the localized 3MLCT by assuming mode-specific broadening of low-frequency intramolecular vibrational modes. The deuterium effects of the electronic origins of the doped crystal observed by Riesen et al. were in excellent agreement with those predicted for the localized 3MLCT. However, the calculated satellite structures of the localized 3MLCT involving bpy-h8 in [Ru(bpy-h8)(3-x)(bpy-d8)x]2+ (x = 1,2) exhibited only the bpy-h8 vibrational modes, inconsistent with the simultaneous appearance of both bpy-h8 and bpy-h8 modes in the observed spectra. A simulation on the basis of the geometry of the delocalized 3MLCT was in reasonable agreement with an unresolved spectrum observed for a neat crystal of [Ru(bpy)3](PF6)2, which is inconsistent with the assignments of localized 3MLCT on the basis of the electronic origins. The inconsistency of the assignment on the basis of the adiabatic model is discussed in terms of vibronic coupling between the localized 3MLCT states. The 3MLCT state in [Os(bpy)3]2+ seems to vary with the environment: a fully localized 3MLCT in a solution, partially localized in a glass matrix, and delocalized in PF6 salts.