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1.
《Physics letters. [Part B]》1988,215(4):624-628
Lifetimes of yrast states from spin 14 through 40 have been measured in 158Er. The Doppler-shift recoil-distance method was used in conjunction with the multi-Ge detector array HERA, and γγ coincidences were analyzed. The collectivity of the nucleus drops from 200 W.u. to 110 W.u. in the region of the second backbend. By spin 38 it has decreased further to 25 W.u., consistent with a band termination. 相似文献
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Andreoiu C Døssing T Fahlander C Ragnarsson I Rudolph D Aberg S Austin RA Carpenter MP Clark RM Janssens RV Khoo TL Kondev FG Lauritsen T Rodinger T Sarantites DG Seweryniak D Steinhardt T Svensson CE Thelen O Waddington JC 《Physical review letters》2003,91(23):232502
The decay-out process of the yrast superdeformed band in 59Cu has been investigated. The firm determination of spin, parity, excitation energy, and configuration of the states involved in this process constitutes a unique situation for a detailed understanding of the decay-out mechanism. A theoretical model is introduced that includes a residual interaction and tunneling matrix element between bands, calculated in the configuration-dependent cranked Nilsson-Strutinsky model. This interaction causes the decay to occur via a small number of observed doorway states. 相似文献
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Bands of negative-parity levels have been observed in in-beam studies of153Tb and155Ho. The data are qualitatively accounted for in the rotation-alignment model as decoupled bands based on the h11/2 proton orbital. Nuclear Reactions:153Eu(α, 4nγ)153Tb,E=45–55 MeV;150Sm(10B, 5nγ)155Ho,E=60–70 MeV; measuredE γ,I γ (0), γ ? γ coinc.,E e, I e K ,153Tb and155Ho deduced levels,J, π. Ge(Li) and Si(Li) detectors. Enriched targets. 相似文献
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T. Byrski F.A. Beck C. Gehringer J.C. Merdinger Y. Schutz J.P. Vivien J. Dudek W. Nazarewicz Z. Szymański 《Physics letters. [Part B]》1981,102(4):235-238
High spin yrast states of 156Er were investigated using the reactions 141Pr(19F,4nγ) and 123Sb(37Cl, 4nγ), the latter in connection with a sum-crystal. In addition to the backbending at , a second one is found at and the yrast band is extended up to . These results are interpreted in terms of a Hartree-Fock-Bogolyubov Cranking (HFBC) method. It is demonstrated that for deformations in the vicinity of the Strutinsky equilibrium deformation, both a 2qp proton band crossing the yrast band or a 4qp neutron band crossing the yrast band can cause strong secondary backbending. 相似文献
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The microscopic model describing the wobbling motion in fast rotating nuclei is presented and the connection of the parameters describing it with the Coriolis effects at low spins is discussed. 相似文献
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Analytical method for yrast line states in the interacting two—component Bose—Einstein condensate
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The yrast spectrum for the harmonically trapped two-component Bose-Einstein condensate (BEC),omitting the difference between the two components,has been studied using an analytical method.The energy eigenstates and eigenvalues for L=0,1,2,3 are given,We illustrate that there are different eigenstate behaviours between the even L and odd L cases for the two-component BEC in two dimensions.Except for symmetric states,there are antisymmetric states for the permutation of the two components,which cannot reduce to those in a single condensate case when the value of L is odd. 相似文献
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A simple model is derived which allows one to study the structure of the nuclear states in the neighborhood of the “yrast” band. In the present scheme the precession motion plays a role of one of the normal modes of oscillations. (The structure of the dispersion equation for this mode corresponds to the well known classical formula.) Vibrational states associated with quadrupole oscillations of the nuclear shape are determined from a general equation. At slow rotation this equation breaks up into the known equations for β-, Δ- and γ-vibrations and non-collectivized Kπ = 1+ excitations. 相似文献
11.
B. Haas H.R. Andrews O. Häusser D. Horn J.F. Sharpey-Schafer P. Taras W. Trautmann D. Ward T.L. Khoo R.K. Smither 《Physics letters. [Part B]》1979,84(2):178-181
Linear polarization and Doppler shift recoil-distance decay curves for γ-ray transitions deexciting very high spin yrast states up to spin 36? in 152Dy were measured with a delayed-promt γ-γ coincidence technique via the reactions 122Sn (34S, 4n) and 124Sn(32S, 4n), at 150 MeV incident beam energy. The deduced experimental transition probabilities are consistent with those obtained for non-rotational nuclei indicating that the yrast angular momentum originates mainly from the alignment of individual particle spins. 相似文献
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E. Ercolessi G. Morandi M. Roncaglia 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,32(4):489-493
Recent neutron scattering experiments on CsNiCl3 reveal some features that are not well described by the standard nonlinear σ model, nor by numerical simulations, for isolated S
= 1 spin chains. In particular, in real systems at the antiferromagnetic point of the Brillouin zone, the intensity of the continuum
of multiparticle excitations, at T
= 6 K, is about 5 times greater than predicted. Also, the spin gap is higher and the correlation length is smaller than predicted.
We propose a theoretical scenario where the interchain interaction is approximated by an effective staggered magnetic field,
and that yields a correct prediction for the observed quantities.
Received 2 October 2002 / Received in final form 19 March 2003 Published online 7 May 2003 相似文献
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S. Perries A. Astier L. Ducroux R. Duffait Y. Le Coz M. Meyer N. Redon F. Azaiez S. Bouneau C. Bourgeois R. Collatz I. Deloncle B. J. P. Gall F. Hannachi I. Hibbert A. Korichi A. Lopez-Martens R. Lucas V. Méot N. Poffé M. G. Porquet C. Schück H. Sergolle J. F. Sharpey-Schafer R. Wadsworth A. N. Wilson 《Zeitschrift für Physik A Hadrons and Nuclei》1996,354(1):1-2
The francium isotopes200–202Fr were produced in the reaction35Cl+170Yb using bombarding energies of 4.9–5.3 MeV/nucleon. Fusion products were separated in-flight from the primary beam using
a gas-filled recoil separator. An alpha line with the alpha particle energy and half-life of (7468±9) keV and (19
−6
+13
) ms, respectively, was assigned to200Fr. Previously reported decay properties of201,202Fr were confirmed.
Communicated by V. Metag 相似文献
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K. M. Nollett 《Few-Body Systems》2008,43(1-4):143-148
I discuss calculations of nuclear properties using the variational Monte-Carlo (VMC) and Green’s function Monte-Carlo (GFMC) methods in combination with realistic two- and three-nucleon interactions. Work to date has emphasized energies of bound and narrow states, and the results agree well with measured masses and energies. We are now directing more effort toward other nuclear properties, including weak decay rates and nuclear charge radii. The main new direction is the computation of low-energy scattering and reaction properties. We have incorporated R-matrix-like boundary conditions into GFMC calculations, and our first calculation of this kind has yielded phase shifts for neutron scattering on 4He up to a few MeV. We find strong dependence of the results on the three-nucleon interaction used. 相似文献
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The yrast line of 42Ca has been investigated with the reaction by means of an anti-Compton γ-spectrometer. The particular feeding and structure of the yrast line in 42Ca up to J=14 is understood by weak-coupling calculations. 相似文献
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《Nuclear Physics A》1997,617(1):91-130
High-spin states in 179Ta have been studied by a variety of γ-ray spectroscopic techniques following the 176Yb(7Li,4n) reaction. The new results independently confirm and extend the one-, three- and five- quasiparticle bands proposed previously. The more comprehensive results obtained allow firm spin assignments to be made and also the identification of rotational bands associated with the higher seniority intrinsic states. Configuration assignments follow from analysis of these rotational band properties. To explain changes in the yrast line across the chain of isotopes from 173Ta to 179Ta, multi-quasiparticle calculations have been performed and compared with experiment. The calculations, which treat pairing correlations using the Lipkin-Nogami approach and include blocking, incorporate single-particle energies adjusted to reproduce the observed one-quasiparticle bandheads. Properties specific to 179Ta include evidence for configuration mixing in the isomer configuration. Its decay is one of several anomalously fast K-hindered transitions observed and discussed in terms of configuration changes and other mechanisms. 相似文献
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XiaoYing Qu Ying Chen ShuangQuan Zhang PengWei Zhao Ik Jae Shin Yeunhwan Lim Youngman Kim Jie Meng 《中国科学:物理学 力学 天文学(英文版)》2013,56(11):2031-2036
Nuclear masses ranging from O to Ti isotopes are systematically investigated with relativistic continuum Hartree-Bogoliubov (RCHB) theory, which can provide a proper treatment of pairing correlations in the presence of the continuum. From O to Ti isotopes, there are 402 nuclei predicted to be bound by the density functional PC-PK1. For the 234 nuclei with mass measured, the root mean square (rms) deviation is 2.23 MeV. It is found that the proton drip-lines predicted with various mass models are roughly the same and basically agree with the observation. The neutron drip-lines predicted, however, are quite different. Due to the continuum couplings, the neutron drip-line nuclei predicted are extended further neutron-rich than other mass models. By comparison with finite-range droplet model (FRDM), the neutron drip-line nucleus predicted by RCHB theory has respectively 2(O), 10(Ne), 10(Na), 6(Mg), 8(Al), 6(Si), 8(P), 6(S), 14(K), 10(Ca), 10(Sc), and 12(Ti) more neutrons. 相似文献
20.
F. Azgui H. Emling E. Grosse C. Michel R.S. Simon W. Spreng H.J. Wollersheim T.L. Khoo P. Chowdhury D. Frekers R.V.F. Janssens A. Pakkanen P.J. Daly M. Kortelahti D. Schwalm G. Seiler-Clark 《Nuclear Physics A》1985,439(3):573-588
Measurements of feeding times of high-spin yrast states up to spin 30 ? in 154Dy and 36 ? in 152 Dy were utilized to obtain information about possible spin-dependent shape changes. The reactions 25Mg(134Xe, 5n), 124Sn(34S, 4n) and 25Mg(132Xe, 5n), 122Sn(34S, 4n) were used to populate the high-spin states in 154Dy and 152Dy, respectively. Feeding times as well as lifetimes were determined with the recoil-distance technique. In 152Dy only long feeding times (? 10 ps) could be identified, indicating that the aligned-particle yrast states are fed through configurations of similar character, with little direct population from collective cascades in the continuum region. In 154Dy discrete states with I ? 30 ? have lifetimes which are characteristically collective, whereas the preyrast cascades exhibit both fast (?1 ps) and slow (~10 ps) feeding components. The latter imply a change with increasing spin from collective to aligned-particle character, probably associated with a prolate to oblate shape transition. 相似文献