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1.
The experimental rotational spectra of the deformed nuclei available in even-even and odd-A nuclei in the rare-earth and actinide regions are systematically analyzed with several rotational spectra formulas,including Bohr-Mottelson's I(I+l)-expansion,Harris'w2-expansion,ab and abc formulas.It is shown that the simple 2-parameter ab formula is much better than the widely used 2-parameter Bohr-Mottelson's AB formula and Harris'αβ formula.The available data of the rotational spectra of both ground-state band in even-even nuclei and one-quaasiparticle band in odd-A nuclei can be conveniently and rather accurately reproduced by ab formula and abc formula.The moment of inertia and the variation with rotational frequency of angular momentum can be satisfactorily reproduced by ab and abc formulas. 相似文献
2.
ZHANG Jing-Ye 《中国物理C(英文版)》1991,15(8):754-760
A method for extracting the empirical proton-neutron interaction energy between the last proton and the last neutron,δVpn has been discribed and developed.The results for ground states of all even-even nuclei with N not less than 40 and for high spin states of some nuclei have been discussed.δVpn values at high frequency for given configuration of some odd a nuclei were shown as well.It is found that these empirical δVpn values include all multipole (mostly the monopole and quadrupole) terms of proton-neutron interaction and sensitively depend on nuclear deformation,configuration and rotational frequency. 相似文献
3.
A. A. Kurteva V. E. Mitroshin 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(6):881-884
The β decay of around 30 odd nuclei was calculated within the dynamic collective model using expressions for the reduced matrix
elements of the weak-interaction Hamiltonian for U-type and V-type β decay obtained earlier by the authors. All of the many-phonon states of the yrast band of an even-even core contributing
to the formation of the excited states of nuclei were taken into account. For β transitions with an intensity of >1%, the
calculated logft values differ from the experimental values by no more than 0.2. 相似文献
4.
We will present results on an collective ΔI = 2 ground band level sequence in the spherical six-valence-particle nucleus 152Dy and the variation of shapes for nuclei in the N = 88 to 92 transitional region. Finally, we will present results for some even-even nuclei without any backbending behaviour, showed a clear backbending in the diagram of 2??/?2 versus (?ω)2. 相似文献
5.
E. Mergel C.M. Petrache G. Lo Bianco H. Hübel J. Domscheit D. Roßbach G. Schönwaßer N. Nenoff A. Neußer A. Görgen F. Becker E. Bouchez M. Houry A. Hürstel Y. Le Coz R. Lucas Ch. Theisen W. Korten A. Bracco N. Blasi F. Camera S. Leoni F. Hannachi A. Lopez-Martens M. Rejmund D. Gassmann P. Reiter P.G. Thirolf A. Astier N. Buforn M. Meyer N. Redon O. Stezowski 《The European Physical Journal A - Hadrons and Nuclei》2002,15(4):417-420
The even-even nucleus 136Nd was studied via in-beam γ-ray spectroscopy using the 16O + 125Te reaction at 100 MeV and the EUROBALL array. One new dipole band was observed. Together with a previously identified dipole
band, whose position in the level scheme is revised, the new band forms a doublet structure similar to the recently observed
chiral bands in the odd-odd neighboring nuclei. This would be the first case of a chiral doublet in an even-even nucleus.
Received: 23 May 2002 / Accepted: 30 September 2002 / Published online: 27 November 2002
RID="a"
ID="a"e-mail: costel.petrache@unicam.it
RID="b"
ID="b"Present address: Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
RID="c"
ID="c"Present address: Gesellschaft für Schwerionenforschung D-64291 Darmstadt, Germany.
Communicated by C. Signorini 相似文献
6.
The Viola-Seaborg formula is a well-known formula for α-decay half-lives of heavy nuclei. In this work we obtain new parameters
of this formula through a least-square fit to even-even nuclei between Z = 84 and Z = 110 with N greater than 126. On average, the formula can reproduce the half-lives of heavy even-even nuclei within a factor of 1.3.
The formula with new parameters works well for the superheavy region which is a hot topic of nuclear physics. The numerical
results from the formula are compared with those from the cluster model. 相似文献
7.
Ts. Venkova W. Gast R. M. Lieder D. Bazzacco G. de Angelis E. O. Lieder A. A. Pasternak R. Menegazzo S. Lunardi C. Rossi Alvarez C. Ur T. Martinez M. Axiotis D. Napoli W. Urban T. Rzaca-Urban S. Frauendorf 《The European Physical Journal A - Hadrons and Nuclei》2005,26(1):19-24
High-spin states in the neutron-rich nuclei 172,173Yb have been populated in a 170Er(7Li,(p,d,t)xn) incomplete-fusion reaction and the emitted γ-radiation was detected with the GASP array. The signature partners of the
7/2+[633] rotational band of the odd-N 173Yb isotope have been newly established and were observed up to spin values of (45/2+) and (43/2+), respectively. The ground-state band of the even-even nucleus 172Yb has been observed up to a spin value of (22+). No band crossings were found in these bands. To explain this observation, it is proposed that the static pair field is
absent, considering that the neutron odd-even mass differences reach for these nuclei very small values and that the band
crossing is absent in cranked shell modell calculations without pairing. The results indicate, however, that strong dynamic
correlations are still present. 相似文献
8.
A comprehensive review of the experimental data for 14.5 MeV neutron induced reaction crosssections for (n, α) reaction has been made for the isotopes having Z up to 82. Two different parameter groups have been considered by the classification
of nuclei into odd-mass and even-even nuclei. The empirical formulae with two parameters for the evaluation of (n, α) reaction cross-sections are discussed in the present study. The odd-even effects have been observed as the cross-sections
of odd-mass nuclei are higher as compared to their neighboring even-even nuclei. The shell effects have also been established
at magic nucleon numbers for these reaction cross-sections. 相似文献
9.
The backbending in even-even rare earth nuclei is analysed in a systematic way by assuming a constant interaction between the ground state rotational band and the lowest excited even parity band, the so-called s-band. 相似文献
10.
The interaction of the rotational three-band, the superband, the g band and theβ band (or γ band), for even-even Nuclei is discussed. The Hamiltonian matrix is diagonalized after solving the secular equation bywhich the parameters in the matrix elemen s are determined. The three-band spectrafor more than ten nuclei have been calculated. The calculated results are found to bein resonable agreement with experimental data, and some informations of three-bandmixing are obtained. 相似文献
11.
B. S. Ishkhanov M. E. Stepanov T. Yu. Tretyakova 《Moscow University Physics Bulletin》2014,69(1):1-20
The nucleon pairing effect that is analyzed in the present paper is one of the striking manifestations of nuclear dynamics. Nucleon pairing for different chains of nuclei dependent upon the number of protons or neutrons in the nucleus allows one to explain the emergence of a great number of positive-parity states, which form a ground state multiplet, in even-even nuclei in the excitation energy range E* < 4 MeV. The interaction of paired nucleons with vibrational and rotational degrees of freedom of a nucleus produces a wide variety of excitation spectra of positive-parity states in even-even nuclei. 相似文献
12.
13.
A. Georgieva M. Ivanov P. Raychev R. Roussev 《International Journal of Theoretical Physics》1989,28(7):769-786
A classification of the even-even nuclei withZ20,A-Z-20, in terms of the boson representation of thesp(4,R) algebra is proposed. All even-even nuclei whose valence nucleons occupy the same major nuclear shell are united in two symplectic multiplets and thus treated in a unified way. A qualitative analysis of the spectrum of the 2+ energy levels of the ground (quasiground) bands is carried out. This analysis shows the expediency of the classification scheme proposed—a periodic structure of the same type is observed in the different shells. This periodic structure is especially stable in the case of the heavy and superheavy nuclei. 相似文献
14.
A new formula, which is derived from a deformed rotor model for describing nuclear rotational spectra, is analyzed. The ground band of most even-even rare-earth and actinide nuclei are accurately reproduced using a damped nonlinear least-square fitting procedure for determining parameters of the theory. The results show that energy spectra obtained from a deformed rotor model are more accurate than those from a three-parameter formula based on perturbation theory. 相似文献
15.
D. R. Wiseman A. N. Andreyev R. D. Page M. B. Smith I. G. Darby S. Eeckhaudt T. Grahn P. T. Greenlees P. Jones R. Julin S. Juutinen H. Kettunen M. Leino A. -P. Leppänen M. Nyman J. Pakarinen P. Rahkila M. Sandzelius J. Sarén C. Scholey J. Uusitalo 《The European Physical Journal A - Hadrons and Nuclei》2007,34(3):275-281
γ -ray transitions in the neutron-deficient nuclei 190, 197Po have been identified using the JUROGAM Ge detector array coupled to the RITU gas-filled separator and the GREAT spectrometer.
The yrast band of 190Po has been firmly established through γ -γ coincidences and extended up to a spin and parity of 14+. It displays similar behaviour to its isotones 186Hg and 188Pb above the 4+ level, thus confirming its prolate nature. In 197Po the band built upon the 13/2+ isomer has been extended up to a spin and parity of 33/2+, while the non-yrast band has been observed for the first time. The behaviour of 197Po is found to be similar to that of the nearby even-mass isotopes, which is consistent with the model in which the i
13/2 neutron is weakly coupled to the states in the even-even core. 相似文献
16.
DING Bin-Gang ZHANG Da-Li LU Ding-Hui 《理论物理通讯》2006,46(1):113-118
We calculate the binding energies of Ni, Cu, Xe, Cs, Pt, Au, Np, Pu isotope chains using two interaction parameter sets NL-3 and NL-Z, and compared the relative errors of the even-even nuclei with those of odd-even nuclei and odd-odd nuclei. We find that the errors of binding energy of odd-even and odd-odd nuclei are not bigger than the one of even-even nuclei. The result shows that comparing with even-even nuclei, there is no systematic error and approximation in the calculations of the binding energy of odd-even and odd-odd nuclei with relativistic mean-field theory. In addition, the result is explained theoretically. 相似文献
17.
We calculate the binding energies of Ni, Cu, Xe, Cs, Pt, Au, Np, Pu isotope chains using two interaction parameter sets NL-3 and NL-Z, and compared the relative errors of the even-even nuclei with those of odd-even nuclei and odd-odd nuclei. We find that the errors of binding energy of odd-even and odd-odd nuclei are not bigger than the one of even-even nuclei. The result shows that comparing with even-even nuclei, there is no systematic error and approximation in the calculations of the binding energy of odd-even and odd-odd nuclei with relativistic mean-field theory. In addition,the result is explained theoretically. 相似文献
18.
N. Yoshinaga K. Higashiyama 《The European Physical Journal A - Hadrons and Nuclei》2006,30(2):343-346
Nuclear structure of doublet bands in doubly odd nuclei with mass A ∼ 130 is investigated within the framework of a simple model where the even-even core couples with a neutron and a proton
in intruder orbitals through a quadrupole-quadrupole interaction. The model reproduces quite well the energy levels of doublet
bands and electromagnetic transitions. The staggering of the ratios B(M1;I → I - 1)/B(E2;I → I - 2) of the yrast bands turns out to be described by the chopsticks-like motion of two angular momenta of the unpaired neutron
and the unpaired proton when they are weakly coupled with the core.-1
An erratum to this article is available at . 相似文献
19.
Lattice strain and p-d repulsion affecting electronic structure of wurtzite Zn1-xCdxO alloys
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In the paper, density of states, band structure and electron density difference of Zn1-xCdxO are calculated by first principles, here x varies from 0 to 0.75 at intervals of 0.125, and the band gap obtained from band structure changes from 0.968 eV to 0.043 eV. The lattice strain and p-d repulsion theory are used to investigate variation of the band gap, the results obtained show that the variation is mainly due to the lattice tensile strain. The p-d repulsion in Zn1-xCdxO cannot be neglected. In addition, electron density difference can be used to verify the results. 相似文献
20.
I. Petermann G. Martınez-Pinedo K. Langanke E. Caurier 《The European Physical Journal A - Hadrons and Nuclei》2007,34(3):319-324
We have performed large-scale shell model calculations of the Gamow-Teller strength distributions in N ∼ Z
pf -shell nuclei. These calculations were motivated by the experimental attempts to measure the low-lying GT strength for the
even-even N = Z + 2 or N = Z - 2 nuclei 46Ti , 50Cr , 54Fe and 62Ge , where a sizable low-energy GT strength could be interpreted as reminiscence of SU(4) symmetry; in the limit of exact SU(4) symmetry the GT- strength would be concentrated in a single transition to the lowest T = 0, J = 1+ state in the daughter. We confirm that the SU(4) symmetry is strongly broken by the spin-orbit interaction and by increasing neutron excess. 相似文献