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11.
R.-D. Herzberg N. Amzal J.E. Bastin F. Becker P.M.T. Brew P.A. Butler A.J.C. Chewter J.F.C. Cocks O. Dorvaux K. Eskola J. Gerl P.T. Greenlees N.J. Hammond K. Hauschild K. Helariutta F. Heßberger M. Houry A. Hürstel R.D. Humphreys G.D. Jones P.M. Jones R. Julin S. Juutinen H. Kankaanpää H. Kettunen T.L. Khoo W. Korten P. Kuusiniemi Y. Le Coz M. Leino A.P. Leppänen C.J. Lister R. Lucas M. Muikku P. Nieminen R.D. Page T. Page P. Rahkila P. Reiter Ch. Schlegel C. Scholey G. Sletten O. Stezowski Ch. Theisen W.H. Trzaska J. Uusitalo H.J. Wollersheim 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):205-208
In-beam conversion electron spectroscopy experiments have been performed on the transfermium nuclei 253, 254No using the conversion electron spectrometer SACRED in nearly collinear geometry in conjunction with the gas-filled separator
RITU at the University of Jyv?skyl?. The experimental setup is discussed and the spectra are compared to Monte Carlo simulations.
The implications for the ground-state configuration of 253No are discussed.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: rdh@ns.ph.liv.ac.uk
RID="b"
ID="b"Present address: GANIL, F-14021 Caen, France.
RID="c"
ID="c"Permanent address: IReS Strasbourg, IN2P3-CNRS, F-67037-Strasbourg, France.
RID="d"
ID="d"Present address: CEA/DIF DCRE/SDE/LDN F-91680 Bruyeres-le-Chatel.
RID="e"
ID="e"Present address: Daresbury Laboratory, Daresbury WA4 4AD, UK.
RID="f"
ID="f"Permanent address: IPN Lyon, IN2P3-CNRS, F-69037 Lyon, France. 相似文献
12.
G.I. Japaridze S. Sarkar 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,28(2):139-144
A one-dimensional model of interacting electrons with on-site U, nearest-neighbor V, and pair-hopping interaction W is studied at half-filling using the continuum limit field theory approach. The ground state phase diagram is obtained for
a wide range of coupling constants. In addition to the insulating spin-density wave (SDW) and charge-density wave (CDW) phases
for large U and V, respectively, we identify a bond-charge-density-wave (BCDW) phase W < 0, | U - 2V| < | 2W| and a bond-spin-density-wave (BSDW) for W > 0, | U - 2V| < W. The possibility of bond-located ordering results from the site-off-diagonal nature of the pair-hopping term and is a special
feature of the half-filled band case. The BCDW phase corresponding to an enhanced Peierls instability in the system. The BdSDW
is an unconventional insulating magnetic phase, characterized by a gapless spin excitation spectrum and a staggered magnetization
located on bonds between sites. The general ground state phase diagram including insulating, metallic, and superconducting
phases is discussed. A transition to the η-superconducting phase at | U - 2V| ≪ 2t?W is briefly discussed.
Received 20 February 2002 / Received in final form 11 April 2002 Published online 19 July 2002 相似文献
13.
L. Bartosch P. Kopietz 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,28(1):29-36
We consider the effect of Coulomb interactions on the average density of states (DOS) of disordered low-dimensional metals
for temperatures T and frequencies ω smaller than the inverse elastic life-time 1/τ. Using the fact that long-range Coulomb interactions in two dimensions (2d) generate ln2-singularities in the DOS ν(ω) but only ln-singularities in the conductivity σ(ω), we can re-sum the most singular contributions
to the average DOS via a simple gauge-transformation. If σ(ω) > 0, then a metallic Coulomb gapν(ω) ∝ |ω|/e
4 appears in the DOS at T = 0 for frequencies below a certain crossover frequency Ω
2 which depends on the value of the DC conductivity σ(0). Here, - e is the charge of the electron. Naively adopting the same procedure to calculate the DOS in quasi 1d metals, we find ν(ω) ∝ (|ω|/Ω
1)1/2exp(- Ω
1/|ω|) at T = 0, where Ω
1 is some interaction-dependent frequency scale. However, we argue that in quasi 1d the above gauge-transformation method is on less firm grounds than in 2d. We also discuss the behavior of the DOS at finite temperatures and give numerical results for the expected tunneling conductance
that can be compared with experiments.
Received 28 August 2001 / Received in final form 28 January 2002 Published online 9 July 2002 相似文献
14.
T. Ishii M. Asai A. Makishima I. Hossain P. Kleinheinz M. Ogawa M. Matsuda S. Ichikawa 《The European Physical Journal A - Hadrons and Nuclei》2002,13(1-2):15-19
Nuclei in the neutron-rich Ni region have been studied by γ-ray spectroscopy. Gamma-rays emitted from isomers, with T
1/2 > 1 ns, produced in heavy-ion deep-inelastic collisions were measured with an isomer-scope. The nuclear structure of the
doubly magic 68Ni and its neighbor 69,71Cu is discussed on the basis of the shell model. Future experiments for more neutron-rich Ni nuclei are also viewed.
Received: 1 May 2001 / Accepted: 4 December 2001 相似文献
15.
H. Sakurai 《The European Physical Journal A - Hadrons and Nuclei》2002,13(1-2):49-53
Recent studies on nuclear structure by using radioactive isotope beams available at the RIKEN projectile-fragment separator
(RIPS) are introduced. Special emphasis is given to two selected experiments from recent programs that highlight studies on
the magicity loss observed for very neutron-rich nuclei beyond N = 20 in the “island-of-inversion” region; the particle stability of 31F, and the low-lying excited states of 34Mg.
Received: 1 May 2001 / Accepted: 4 December 2001 相似文献
16.
17.
R. Ramaswamy 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):339-343
Integrable dynamical systems, namely those having as many independent conserved quantities as freedoms, have all Lyapunov
exponents equal to zero. Locally, the instantaneous or finite time Lyapunov exponents are nonzero, but owing to a symmetry,
their global averages vanish. When the system becomes nonintegrable, this symmetry is broken. A parallel to this phenomenon
occurs in mappings which derive from quasiperiodic Schr?dinger problems in 1-dimension. For values of the energy such that
the eigenstate is extended, the Lyapunov exponent is zero, while if the eigenstate is localized, the Lyapunov exponent becomes
negative. This occurs by a breaking of the quasiperiodic symmetry of local Lyapunov exponents, and corresponds to a breaking
of a symmetry of the wavefunction in extended and critical states.
Received 25 October 2001 / Received in final form 8 December 2001 Published online 2 October 2002
RID="a"
ID="a"e-mail: r.ramaswamy@mail.jnu.ac.in 相似文献
18.
Electrical impedance measurements of Na3H(SO4)2 were performed as a function of both temperature and frequency. The electrical conductivity and dielectric relaxation have been evaluated. The temperature dependence of electrical conductivity reveals that the sample crystals transformed to the fast ionic state in the high temperature phase. The dynamical disordering of hydrogen and sodium atoms and the orientation of SO4 tetrahedra results in fast ionic conductivity. In addition to the proton conduction, the possibility of a Na+ contribution to the conductivity in the high temperature phase is proposed. The frequency dependence of AC conductivity is proportional to ωs. The value of the exponent, s, lies between 0.85 and 0.46 in the room temperature phase, whereas it remains almost constant, 0.6, in the high-temperature phase. The dielectric dispersion is examined using the modulus formalism. An Arrhenius-type behavior is observed when the crystal undergoes the structural phase transition. 相似文献
19.
Jianjun Liu Chun-gang DuanM.M Ossowski W.N MeiR.W Smith J.R Hardy 《Journal of Physics and Chemistry of Solids》2002,63(3):409-414
Structural phase transition in AgNO3 at high temperature is simulated by molecular dynamics. The simulations are based on the potentials calculated from the Gordon-Kim modified electron-gas formalism extended to molecular ionic crystals. AgNO3 transforms into rhombohedral structure at high temperature and the phase transition is associated with the rotations of the NO3 ions and displacements of the NO3 and Ag ions. 相似文献
20.
The high-temperature cubic phase of non-stoichiometric strontium ferrite SrFeOx (2.5≤x≤3.0) has been studied by in situ neutron powder diffraction in air over the temperature range 300-1273 K. The composition of SrFeOx changes within the range 2.56≤x≤2.81 from 1273 to 673 K, respectively.Rietveld refinements of the diffraction patterns show that the high-temperature cubic phase of SrFeOx is consistent with a face-centred Fm3c structure. This structure leads to agreement with previous density measurements. This cell allows the high-temperature structure of SrFeOx to be described in terms of a solid solution of the composition end members. Cubic SrFeOx at high temperature is found to closely obey Vegard's law. The density of cubic SrFeOx is also found to exhibit a linear relationship with composition. 相似文献