Theoretical response to the discovery of deeply bound pionic states in208Pb(d,3He) reactions

Recently, deeply bound pionic states were found experimentally in (d,³He) reactions on²⁰⁸Pb. They found an isolated peak structure in the bound region below the pion production threshold. We study theoretically these excitation functions in (d,³He) reactions on²⁰⁸Pb at T _d =600 MeV. We found very good agreement with the (d,³He) excitation functions and could identify the underlying structures of the pionic states. We study the energy dependence of the (d,³He) reactions and the change of the excitation functions with the incident energy.     

Appearance of magnetic long range order in the spin ladder compound LaCuO2.5

We report here the two current topics in the ladder compounds. 1. The new ladder compound LaCuO_2.5 recently discovered by Hiroi and Takano shows a clear sign of magnetic long range order at around 125 K observed by μ⁺SR technique. This result demonstrates that the ground state of LaCuO_2.5 is not a spin liquid state, but a magnetically ordered state. 2. Superconductivity has been found in the ladder material (Sr,Ca)₁₄Cu₂₄O₄₁ under high pressure between 3 GPa and 4.5 GPa. The superconducting transition temperatures T_c (onset) are 12 K and 9 K at 3 GPa and 4.5 GPa, respectively. This revised version was published online in July 2006 with corrections to the Cover Date.     

Catalytic epoxidation of cyclohexene by covalently linked manganese porphyrin–viologen complex

When a viologen-linked Mn(III)porphyrin complex with a short methylene-chain, in which a viologen is covalently linked by the methylene-chain into one phenyl group of 5,10,15,20-tetraphenylporphyrinatomanganese(III)chloride (Mn(III)(tpp)Cl), was used as a catalyst for a monooxygenation of cyclohexene in an air-equilibrated acetonitrile solution containing insoluble zinc powder as a reductant, more cyclohexene oxide was obtained as a single product than when Mn(tpp)Cl was used as a catalyst. Benzoic acid as a cleaving reagent of the dioxygen double-bond and 1-methylimidazole as a ligand to Mn porphyrin were further contained in the reaction mixture. This result implies that the viologen moiety in the viologen-linked Mn(III)porphyrin acted effectively as a mediator for electron transfer from zinc powder to the Mn(III)porphyrin moiety in the epoxidation cycle activating molecular dioxygen reductively. Though Mn(tpp)Cl was remarkably demetallated by H⁺ ion from benzoic acid during the epoxidation reaction in the mixed system of Mn(III)(tpp)Cl and viologen, the demetallation of the viologen-linked Mn porphyrin with the short methylene-chain was partly prevented because the reduction of a Mn(II)porphyrin-dioxygen adduct was easily caused by fast intramolecular electron-transfer between the two moieties of the viologen and the Mn porphyrin, proceeding the epoxidation cycle smoothly.     

Preparation and magnetic properties of ultrafine particles of FeNi alloys

Ultrafine particles (UFP) of six kinds of FeNi alloys were synthesized by the method of hydrogen plasma reaction. The prepared UFP samples were examined by X-ray diffraction, electron transmission microscopy and magnetic measurement. The spherical FeNi UFP alloys with a mean particle size less than 35 nm can be prepared with a production rate much higher than by conventional methods. The phase constitution of UFP alloys is different from the equilibrium phase diagram owing to rapid condensation of evaporated metal gases. Although the magnetization for the UFP alloys has almost the same temperature dependence as that of the bulk alloys, the saturation magnetization remarkably decreases as the bulk alloys change into the UFP alloys.     

Asymmetric reactions with cyclodextrins

Cyclodextrins have great potential for exploitation as a useful tool for asymmetric induction. Many kinds of asymmetric reaction have been achieved in the presence of cyclodextrin under various conditions such as the solid phase, heterogeneous suspension or homogeneous aqueous or organic solution. Complexation is essential for asymmetric induction. What is necessary to improve CDs for greater asymmetric induction?     

Laser-Diode Phase-Shifting Joint-Transform Correlator with Multiple-Object Recognition

A joint-transform phase correlation is made by an extracted phase from the joint power spectrum using a phase-shifting Mach-Zehnder interferometer with a wavelength-shifted laser diode (LD), and then by numerically Fourier-transforming a measured phase. The algorithm in six steps is insensitive to the power changes in an LD. The phase correlator gives the best discrimination performance. Discriminative multiple-object recognition is performed with no intermodulation noise and artifact noise-free correlation by arranging the multiple objects in a regularly equal-spaced array. The experimental and numerical results are shown.     

Theoretical study on the excited states of psoralen compounds bonded to a thymine residue

Time-dependent density functional theory calculations have been performed for the excited states of psoralen, 5-methoxypsoralen, and 8-methoxypsoralen in systems and furan and pyrone monoadducts bonded to a thymine residue. The theoretical assignments to ultraviolet (UV) absorption spectra of isolated systems have been performed. The present calculations have clarified that the excitation energies of the first singlet excited (S1) state of monoadducts are blue-shifted compared with the isolated systems. It is shown that, in particular, the S1 excitation energy of the pyrone monoadduct is significantly blue-shifted and, therefore, the pyrone monoadduct is not excited by UV-A light (300-400 nm), which is used in the photochemotherapy.