No abstract available

[en] We report on pair-truncated shell-model calculations of low-lying yrast and quasi-γ bands of nuclei around mass 130 using phenomenological effective interactions of pairing plus quadrupole type, where the strengths of interactions are gradually changed as functions of numbers of valence nucleons. The calculations start with even-even nuclei of low-lying states, which exhibit typical features of γ-instability. The model reproduces well experimental energy levels and E2 transition rates. We calculate energy levels of odd-A nuclei, where the effective interactions identical to those obtained from the calculations of the even-even nuclei are employed. The agreement between the theoretical values and the experimental observations is rather well. (author)

[en] Backbending phenomena and low-lying collective states in the nucleus ¹³²Ba are studied in terms of a pair-truncated shell model with the monopole and quadrupole pairing plus quadrupole-quadrupole interaction. The model reproduces well experimental energy levels, transition rates, and g factors for both low-lying states and those around the backbending region. The collective pair truncation of the shell-model space yields remarkable results for low-lying states, and the alignment of two 0h_11/2 neutrons plays a decisive role in describing the backbending

[en] The quantum-number-projected generator coordinate method with the monopole- and quadrupole-pairing plus quadrupole-quadrupole interaction is studied in reference to the low-lying and high-spin states in ^130,132Xe. The energy spectra obtained by this method are compared to the shell model results and the experimental data. The quasi-γ bands as well as the yrast sequences are well reproduced. The triaxial shapes play essential roles in describing the quasi-γ bands

[en] Xe isotopes near mass A∼130 region, which exhibit features of O(6) symmetry at low energy and the backbending at high spins, are studied in the shell model framework. The monopole and quadrupole pairing plus quadrupole-quadrupole interaction is employed as an effective interaction. As for single-particle levels, the 1d_3/2, 0h_11/2, 2s_1/2 orbitals are taken into account for neutrons and the 1d_5/2, 0g_7/2 orbitals for protons under the assumption of N=Z=64 subshell closure. The calculation reproduces the experimental energy levels of high-spin states as well as low-lying states well. This is the first successful microscopic description of the backbending in this mass region. The shell model states are examined in pair-truncated models. The analysis shows the alignment of two 0h_11/2 neutrons at high spins

[en] We have measured the temperature dependence of valence and core x-ray photoelectron intensities for W(110). At 295 K, valence spectra are very sensitive to emission direction due to direct-transition effects, and Ienergy-integratedR valence and core photoelectron diffraction curves are similar in form, but with significant differences in fine structure. At 803 K, valence spectra are by contrast very insensitive to direction due to increased zone averaging, but valence and core diffraction curves retain differences due to the atomic-orbital character of the initial and final states involved

No abstract available

[en] We have found a very effective way to control the orientation of YBa₂Cu₃O_7-δ (YBCO) high-temperature superconducting thin films grown by the metalorganic chemical vapor deposition (MOCVD) on MgO (100) substrate using an ArF excimer laser (λ=193nm). It also enables us to control crystalline orientation locally by focusing the laser. We found that the irradiated parts prepared at 650-700degC were strongly a-axis orientation. The surface morphology of the laser irradiated part of the films was very smooth. The zero-resistance temperature of the irradiated part of YBCO prepared at 650degC was 72K. (orig.)

[en] A simple model is applied to the yrast and yrare states based on the νh_11/2 x πh_11/2 configuration in the doubly-odd nuclei around the mass 130. In the model, the basis state is constructed by one neutron and one proton both in the 0h_11/2 orbital, and by the collective core which couples with the two particles through a quadrupole interaction. The model reproduces quite well the overall energy levels and the electromagnetic transitions. The analysis of the yrast and yrare states reveals that the angular-momentum configuration of the neutron and the proton in the yrast states is different from that in the yrare states, when the two particles are weakly coupled with the quadrupole collective excitations of the core. The strong even-odd staggering of the ratios B(M1;I→I-1)/B(E2;I→I-2) for the yrast states is described by the chopsticks-like motion of two angular momenta of the neutron and the proton. (orig.)

[en] The nuclear structure of polonium and radon isotopes is theoretically studied in terms of the spherical shell model with the monopole- and quadrupole-pairing plus quadrupole-quadrupole effective interaction. The experimental energy levels of low-lying states are well reproduced. The shell model results are examined in detail in a pair-truncated shell model (PTSM). The analysis reveals the alignment of two protons in the 0h_9_/_2 orbital at spin 8. (authors)