Multiple octupole excitations in 148Gd

The lifetime and the -decay to the 0⁺ ground state of the lowest 3^- state in ¹⁴⁸Gd has been determined. The reduced strength B(E3, 3^- 0⁺)=41 (6) W.u. agrees well with the theoretical value from empirical shell model calculations and can be directly compared with the 12⁺ 9^- two-octupole-phonon one-octupole-phonon strength obtained in the same Recoil Distance Method lifetime measurement. The results of our search for a three octupole-phonon state built on the state is also reported. Received: 7 March 2000 / Accepted: 12 May 2000     

丰中子核63,65,67Mn的在束γ谱学研究

利用放射性束68Fe轰击液氢靶引起的敲出反应,研究了极端丰中子核63,65,67Mn的激发态,指认了它们的自旋宇称,建立了这三个原子核的能级纲图。纲图包含11/2–、9/2–和 7/2– 三个激发态以及$5/2_{\rm{g.s.}}^{-}$基态,它们由三条$\Delta I \!=\! 1$的$\gamma$跃迁连接。这种能级结构与$K \!=\! 5/2$时强耦合转动带的特征一致。使用改进的LNPS有效相互作用(LNPSm)的大规模壳模型计算能很好地重现观测到的能级。计算表明,65,67Mn的低位激发态都主要包含处于$4p{\text -}4h$的中子组态和$1p{\text -}1h$的质子组态。基于实验结果发现,在吸积中子星壳中,与质量数$A \!=\! 63$相关的Urca中微子冷却效果比预期的要强很多,而$A \!=\! 65, 67$的冷却效果比预期的更弱。     

Preparation and thermal properties of a series of mixed calcium-cobalt phosphates

Mixed calcium-cobalt orthophosphates, of the general formula Ca_3-xCO_x(PO₄)₂ with 0≤x≤1.1, were prepared by coprecipitation. Reactions which occur during heating from room temperature to 850°C, of either tricalcium phosphate or mixed Ca?Co phosphates, were monitored by thermogravimetry and differential thermal analysis. The dried precipitates and the final products were characterised by X-ray diffraction and infrared spectroscopy.     

DSAM lifetimes of the ground state band in48Cr

Lifetimes have been determined in the ground state band in⁴⁸Cr and found in agreement with Shell Model calculations.     

Approaching the full CI limit with MRD CI calculations: The X 1A1 state of water with a double-zeta basis

Results of MRD CI calculations with varying numbers of reference configurations for the water molecule employing a double-zeta basis set are compared with the corresponding full CI results of Harrison and Handy as well as with those of other methods. For the three geometries considered a highly uniform percentage (99.8±0.1%) of the available correlation energy in this AO basis is obtained by solving secular equations in the 13–15000 range, i.e. only 5% of the full CI space. Extrapolation of the full CI energy through the use of various correction formulae is found to be unreliable for large bond distances, although such an approach is successful at the equilibrium geometry.     

Fractional nonlinear diffusion equation,solutions and anomalous diffusion

We devote this work to investigate the solutions of a generalized diffusion equation which contains spatial fractional derivatives and nonlinear terms. The presence of external forces and absorbent terms is also considered. The solutions found here can have a compact or long tail behavior and, in particular, for the last case in the asymptotic limit, we relate these solutions to the Lévy or Tsallis distributions. In addition, from the results presented here a rich class of diffusive processes, including normal and anomalous ones, can be obtained.     

Fractional approach,quantum statistics,and non-crystalline solids at very low temperatures

We consider nonlocal effects, obtained by incorporating fractional derivatives in the kinetic energy of a conventional Hamiltonian, to analyze physical properties of non-crystalline solids at very low temperature. By using thermal Green functions, we deduce some experimentally observable quantities such as the particle momentum distribution function, the particle energy distribution function, and the specific heat. The agreement between the results obtained for the specific heat and the experimental data suggests that the approach presented here may be useful as a phenomenological model to investigate thermal properties of non-crystalline solids at low temperature.     

Unusual isospin-breaking and isospin-mixing effects in the A=35 mirror nuclei

Excited states have been studied in 35Ar following the 16O(24Mg,1alpha1n)35Ar fusion-evaporation reaction at 60 MeV using the Ge-detector array GASP. A comparison with the mirror nucleus 35Cl shows two remarkable features: (i) A surprisingly large energy difference for the 13/2(-) states, in which the hitherto overlooked electromagnetic spin-orbit term is shown to play a major role, and (ii) a very different decay pattern for the 7/2(-) states, which provides direct evidence of isospin mixing.     

Crystal and molecular structure of dimethylpyrazolo [1,2-a]pyrazolo[1,2-b]benzotriazole-3,4-dicarboxylate,C15H13N3O4

Crystals of dimethyl pyrazolo [1,2-a]pyrazolo[1,2-b]benzotriazole-3,4-di-carboxylate, C₁₅H₁₃N₃O₄, are triclinic:a=9.268(10),b=19.367(50),c=8.821(9) Å,=96.76(18),=115.39(10),=80.17(22)°,Z=4, space group P¯1 with two independent molecules in the asymmetric unit. The crystal and molecular structures have been determined from X-ray diffractometer data by direct methods, and refined by least-squares methods toR=0.047 for 2653 observed reflections. In a least-squares fitting procedure the two independent molecules show an almost perfect resemblance, except for the orientations of the 3-carbomethoxy groups. Their chiral structure is described asS. There is an appreciable puckering of the condensed five-membered rings. Bond distances and angles are found to be not comparable with those in the literature, and are discussed. The carbomethoxy groups of the same molecule show a different slant, owing to overcrowding. Close molecular packing is afforded by layers of molecules approximately parallel to the (001) plane.     

Mapping Properties of the Laplacian in Sobolev Spaces of Forms on Complete Hyperbolic Manifolds

For a complete manifold M with constant negative curvature, weprove that the rough Laplacian _R defines topological isomorphisms in the scale of Sobolev spaces H _p ^s (M) ofp-forms for all p, 0 < p< n. For the de Rham Laplacian and M= ⁿ , the Poincaréhyperbolic space, this is shown too for 0 pn,pn/2, p (n± 1)/2.