Environment potential in Hartree-Fock-Slater formalism

A new formulation of the environment potential approach (EPA) is developed within the Hartree-Fock-Slater framework. As the results of illustrative applications to C₅ cluster which is the smallest unit of diamond lattice, EPA is shown to annul efficiently the fictitious-surface effects which are inevitably brought into a finite-size-cluster model.     

Environment potential in closing bonds case

A method of an electronic structure calculation of cluster is suggested. It consists of an “effective” potential with an electron to close the torn valence bonds which appear inevitably in a finite-size-cluster model. The method is applied to the C₅ cluster representing the diamond lattice and is shown to be effective to nullify the pseudo-surface effects.     

An efficient synthesis of 3-aminoisothiazolo[5,4-b] -quinoline from quinoline

Treatment of readily available 3-formylquinoline-2-thiol ( 1 ) with ammoniacal sodium hypochlorite directly afforded isothiazolo[5,4-b]quinoline ( 3 ) in high yield, probably via 3-formylquinoline-2-sulfenamide ( 2 ). Facile conversion of 3 to the corresponding 3-amino derivative ( 7 ) was accomplished by the following sequence: base induced opening of the isothiazole ring to 3-cyanoquinoline-2-thiol ( 5 ), oxidation of 5 to the corresponding stable sulfenamide ( 6 ) and sodium ethoxide catalysed reclosure of the isothiazole ring which provided 3-aminoisothiazolo[5,4-b]quinoline ( 7 ).     

Study of decay mechanisms in B--->Lambdac+ppi- decays and observation of low-mass structure in the Lambdac+p system

Using a sample of 152 x 10(6) BB pairs accumulated with the Belle detector at the KEKB e+e- collider, we study the decay mechanism of three-body charmed decay B- --> Lambdac+ ppi-. The intermediate two-body decay B--->Sigmac (2455)0 p is observed for the first time with a branching fraction of (3.7 +/- 0.7 +/- 0.4 +/- 1.0) x 10(-5) and a statistical significance of 8.4sigma. We also observe a low-mass enhancement in the (Lambdac+p) system, which can be parametrized as a Breit-Wigner function with a mass of (3.35(-0.02)(+0.01) +/-0.02) GeV/c2 and a width of (0.07(-0.03)(+0.04) +/-0.04) GeV/c2. We measure its branching fraction to be (3.9(-0.7)(+0.8) +/- 0.4 +/- 1.0) x 10(-5) with a statistical significance of 6.2sigma. The errors are statistical, systematic, and that of the Lambdac+-->pK- pi+ decay branching fraction.     

Changes in the fluorescence spectrum of individual single-wall carbon nanotubes induced by light-assisted oxidation with hydroperoxide

Through fluorescence-spectrum measurements, we investigated the effects of light-assisted oxidation with H2O2 (LAOx) on single-wall carbon nanotubes (SWNTs) that were individually dispersed in an aqueous solution of surfactant. The intensities of the fluorescence spectra were decreased remarkably by the LAOx when the light's wavelength was 400-500 nm and a little when 600-700 nm. The spectrum intensity did not recover even when the pH was restored to an original value of 6.5. The spectra changed little when the LAOx wavelength was 500-600 nm or the light was not irradiated. In addition, the effect of LAOx on SWNTs was related to the diameters of SWNTs. We inferred that these phenomena reflected that H2O2 was dissociated by absorbing the fluorescence light emitted from optically excited SWNTs, which, in turn, accelerated the burning out of SWNTs.     

Precise nuclear moments of extremely proton-rich nuclus 23 Al

Electric quadrupole coupling constant eqQ/h of the extremely proton-rich ²³Al (I ^π ?=?5/2^?+?, T _1/2?=?0.47 s) nucleus implanted into an Al₂O₃ single crystal has been measured for the first time, using the β-ray detecting nuclear quadrupole resonance method (β-NQR) in a high magnetic field. As a preliminary result, the quadrupole coupling constant was determined as |eqQ/h(²³Al) |?=?2.66±0.77 MHz. Using the quadrupole coupling constant of ²⁷Al in Al₂O₃ as a reference, the Q moment of the ground state of ²³Al was extracted as |Q(²³Al)|?~?160 mb, which is well explained by the shell model calculation in the sd-shell model space with the USD interaction.     

First measurement of inclusive B→Xsη decays

We report a first measurement of inclusive B→Xsη decays, where Xs is a charmless state with unit strangeness. The measurement is based on a pseudoinclusive reconstruction technique and uses a sample of 657×10(6)BB pairs accumulated with the Belle detector at the KEKB e+e- collider. For MXs < 2.6 GeV/c2, we measure a branching fraction of [26.1±3.0(stat)-2.1+1.9(syst)-7.1+4.0(model)]×10(-5) and a direct CP asymmetry of ACP=-0.13±0.04-0.03+0.02. Over half of the signal occurs in the range MXs > 1.8 GeV/c2.