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1.
R. Schubart H. Grawe J. Heese H. Kluge K. H. Maier M. Schramm 《Zeitschrift für Physik A Hadrons and Nuclei》1995,352(4):373-390
The neutron deficient nuclei98Ag,104Sn withT
z
=2 and103In,105Sn (T
z=5/2) were studied in-beam following the reaction of 250 MeV58Ni+50Cr. Neutron and charged particle (p, ) gated-coincidence spectra were used to identify these nuclei, which are populated with yields between 0.05% and 2% of the total residue cross section, and to determine their level schemes. In a comprehensive shell model study various approaches for the residual interaction were used to describe these newly and several previously studied neutron deficient nuclei. As a result predictions for the neutron single particle energies for100Sn are obtained and used to discuss the next generation of experiments.The authors gratefully acknowledge the assistance of L. Käubler and H. Rotter in the experiment, of R. Jerecic in the centroid shift analysis, and fruitful discussions with D. B. Fossan, D. Seweryniak and our collegues from the NORDBALL collaboration. 相似文献
2.
V. L. Litnevsky G. I. Kosenko F. A. Ivanyuk V. V. Pashkevich 《Physics of Atomic Nuclei》2012,75(1):37-44
The effect of the shell structure of colliding nuclei in calculating the entrance channel on the ensuing evolution of the
product system is investigated. The entrance channel is calculated under the assumption of the nose-to-nose orientation of
colliding nuclei. The following three reactions involving nuclei that are deformed in the ground state are considered: 42100Mo + 42100Mo → 84100Po, 42100Mo + 46100Pd → 88210Ra, and 46110Pd + 46110Pd → 92220U. The state of the system at the point of touching is determined by the results obtained by calculating the entrance reaction
channel. The shape of the system is specified by three collective coordinates (deformation parameters). The evolution of collective
coordinates of the system is described in terms of Langevin equations. The potential energy of the system of colliding nuclei
is calculated with allowance for their shell structure. It is shown that allowance for individual features of interacting
nuclei in the entrance channel of the fusion-fission reactions makes it possible to obtain, for the reactions being considered,
cross sections for evaporation-residue formation that are closer to available experimental data than their liquid-drop counterparts. 相似文献
3.
Using a theory of mode-mode coupling between the two-phonon 0+ mode and the pairing-vibrational mode, we have extensively investigated the first excited 0+(022) states in spherical and transitional nuclei. The results tell us that the 02+ states in a wide range of nuclei are strongly mixed states of both the modes. By making use of these results, the matrix elements for the E0 transitions from the 02+ states to the ground states are calculated for the Zn, Ge, Se, Kr, Sr, Zr, Mo, Ru, Pd, Cd and Sn isotopes. For some of the Cd and Sn isotopes, the matrix elements between the 02+ and 02+ states are also obtained. These numerical calculations make a rather good fit to the E0 experiments. 相似文献
4.
Predictions for cross sections of light proton-rich isotopes in the ~(40)Ca + ~9Be reaction 下载免费PDF全文
The cross sections for Z=10–19 with isotopes T_z=-3/2 to-5 in the 140A Me V~(40)Ca+~9Be projectile fragmentation reaction have been predicted.An empirical formula based on the correlation between the cross section and average binding energy of an isotope has been adopted to predict the cross section.The binding energies in the AME16,WS4,and the theoretical prediction by the spherical relativistic continuum Hartree-Bogoliubov theory have been used.Meanwhile,the fracs parametrization and the modified statistical abrasion-ablation model are also used to predict the cross sections for the proton-rich isotopes.The predicted cross sections for the T_z=-3 isotopes are close to 10~(-10)mb,which hopefully can be studied experimentally.In addition,based on the predicted cross sections,Z=14 is suggested to be a new magic number in the light proton-rich nuclei with T_z-3/2,for which the phenomenon is much more evident than it is from the average binding energy per nucleon. 相似文献
5.
D. Alber H. H. Bertschat H. Grawe H. Haas B. Spellmeyer 《Zeitschrift für Physik A Hadrons and Nuclei》1989,332(2):129-135
The neutron deficient nucleus96Pd, four proton holes below the doubly magic100Sn, has been studied in the reaction64Zn (36Ar, 2p 2n). Innγ andγγ coincidences levels up to 7 MeV excitation energy were established, and a new neutron core-excited isomer with T1/2=35(4)ns and g=0.83 (5) was identified. A detailed shell model study yields excellent agreement for states within the π(p1/2,g9/2) configuration space but fails to reproduce the isomerism andg-factor for the core-excited state. 相似文献
6.
G. le Caër B. Malaman G. Venturini H. G. Wagner U. Gonser 《Hyperfine Interactions》1986,28(1-4):631-634
57Fe and119Sn Mössbauer spectra have been recorded at 100 K in applied fields of 32 and 64 kG on a FeSn2 sample obtained by arranging single crystal needles side by side. The present work confirms that the Sn fields are anisotropic above Tt=93 K. The field model has been used to determine the magnetic structure of FeSn2 below Tt. 相似文献
7.
The hyperfine fields acting on119Sn nuclei in the RT2 (R=Sm?Lu; T=Fe, Co, Ni) have been measured by Mössbauer spectroscopy. It has been found that the hyperfine fields acting on119Sn nuclei in the RT2 compounds are changed at some electronic occupation of the 4f shell of the R-component. The occupation of 4f shell is varied with the T-component. The sharp change of the hyperfine fields are connected with the change of the electronic band structure. 相似文献
8.
We discuss the systematics of 0+, v = 0, T = |TZ| + 1 levels in odd-odd nuclei and conclude about the ground state isospin and seniority of these nuclei. For N = Z nuclei starting from the shell vg.s = 0 |Tg.s = |Tz + 1. Otherwise vg.s = 2, Tg.s = |Tz|. 相似文献
9.
V. Koponen J. Äystö J. Honkanen P. Jauho H. Penttilä J. Suhonen P. Taskinen K. Rykaczewski J. Żylicz C. N. Davids 《Zeitschrift für Physik A Hadrons and Nuclei》1989,333(4):339-348
Neutron-rich isotopes of palladium were produced via the fission of238U by 20 MeV protons. These isotopes were selected using the ion guide-fed on-line mass-separator facility IGISOL at Jyväskylä. Their decays were studied byβ-ray,γ-ray and conversion-electron spectroscopy. For114Pd and116Pd, the decay schemes established previously were confirmed; additionally multipolarities were determined for a few transitions. In the case of118Pd, only an approximate half-life was known from a previous radiochemical experiment. In the present study, 15 gamma transitions were observed, most of which were placed in a decay scheme. The half-life and the decay energy were found to beT 1/2=1.9±0.1 s andQ β=4.0±0.2 MeV. The decay schemes of114Pd,116Pd and118Pd include — respectively — two, two and four 0+→1+ Gamow-Teller beta transitions with logft values between 4.1 and 5.1. The strength of these transitions is discussed in terms of the extreme single particle shell model with pairing and the spherical proton-neutron quasiparticle random phase approximation. The possible role of deformation is considered using a shell correction method. Predictions for the decay properties of the as yet unobserved120Pd are given. 相似文献
10.
O. N. Bakharev A. V. Dooglav A. V. Egorov V. V. Naletov M. P. Rodionova M. S. Tagirov M. A. Teplov 《Applied magnetic resonance》1991,2(3):559-569
The ground state of Tm3+ ion (4t2,3H6) in a crystal electric field (CEF) of TmBaCuO is a singlet, separated from the lowest excited states by an energy gap of 100÷130 cm?1. The pulsed NMR of169Tm nuclei (spinI=1/2) in a magnetically-oriented TmBa2Cu3O6.92 power is studied at temperatures 1.5÷4.2 K. Two sorts of Tm nuclei are observed: rapidly relaxing Tm1 (≥80% of total amount, having relaxation timesT 1 (1) ≈35 ms,T 2 (1) =80÷250 μs) and slowly relaxing Tm2 nuclei (≦20%,T 1 (2) =300÷1000 μs). The169Tm NMR spectra are described by the spin-Hamiltonian ?1 = ??Σγ i H i I i (i = x,y,z), where |γ x (1)/2π| = 5.3(1), |γ y (1)/2π| = 6.6(1), |γ x (2)/2π| = |γ y (2)/2π| = 5.1(1), |γ z (1)/2π| = |γ z (2)/2π| = 2.3(1) kHz/Oe, and axesx, y, z coincide with the crystal axesa, b, c. The Tm1 and Tm2 nuclei are identified as those belonging to orthorhombic (CEF of D2h symmetry) and tetragonal (D4h) phases of the TmBaCuO compound, respectively. Two-exponential and nearly temperature-independent nuclear relaxation is observed at temperatures 1.5÷4.2 K. The smallestT 2 (1) -values (≈80 μs) found for the orthorhombic (superconducting) phase in an external field H perpendicular to the crystalc-axis agree fairly well with those one could expect due to the dipole-dipole interaction of thulium nuclei. However, the slowing down of this rapid relaxation of the nuclear transverse magnetization in a field H‖c as well as the origin of unusually largeT 2 (2) -values remain unclear. 相似文献
11.
A. Covello L. Coraggio A. Gargano N. Itaco 《The European physical journal. Special topics》2007,150(1):93-96
We report on a study of exotic nuclei around doubly magic 132Sn in terms of the shell model employing a realistic effective interaction derived from the CD-Bonn nucleon-nucleon potential.
The short-range repulsion of the bare potential is renormalized by constructing a smooth low-momentum potential, Vlow-k, that is used directly as input for the calculation of the effective interaction. In this paper we focus attention on the
nuclei
134Sn and 135Sb which, with an N/Z ratio of 1.68 and 1.65, respectively, are at present the most exotic nuclei beyond 132Sn for which information exists on excited states.
Comparison shows that the calculated results for both nuclei are in very good agreement with the experimental data. We present
our predictions of the hitherto unknown spectrum of
136Sn. 相似文献
12.
13.
Strengths of Gamow-Teller decays of Tz = ±1 nuclei to Tz = 0 odd-odd nuclei have been calculated by using spherical shell model and deformed Nilsson wave functions. The role and
competition of the microscopic direct and spin-flip mechanisms generating Gamow-Teller transitions are analyzed. Analytical
expressions derived for the B(GT) values give useful insight into the regularities of B(GT) values along the N = Z line. The crucial role of configuration mixing is discussed. 相似文献
14.
A wide range of research topics in different fields of physics can be addressed by study of the self-conjugate N~Z nuclei, such as the np pairing, isospin symmetry, the rp-process and the properties of the electroweak interaction. This contribution focuses on the spectroscopy of N~Z nuclei towards 100Sn. The latest results on the isomeric decay spectroscopy of N~Z nuclei below 100Sn, such as the N =Z+2 nuclides 94Pd and 96Ag, the N~Z nuclide 96Cd and so on are highlighted. New opportunities in in-beam spectrscopy of N~Z nuclei towards 100Sn, like 90Rh and 92Pd, with radioactive ion beams are discussed. 相似文献
15.
P. van Nes K. Allaart W. H. A. Hesselink Jan Konijn H. Verheul 《Zeitschrift für Physik A Hadrons and Nuclei》1981,301(2):137-140
Theg-factor of theJ π=21/2+ isomeric state in111In (T 1/2=13.3 ns) and of theJ π=6+ isomeric state in112Sn (T 1/2=13.7 ns) were measured using the spin rotation method. The result obtained for theJ π=21/2+ level in111In,g=+0.47 (2), indicates that this state has an almost pure ((πg 9/2)?1 νg 7/2 νd 5/2) shell model configuration. The experimental valueg=+0.04 (3) for theJ π=6+ isomer in112Sn agrees with the theoretical value calculated within the frame of the BCS model. 相似文献
16.
L. Ricken D. Bohle G. Domogala K. Glasner E. Kuhlmann 《Zeitschrift für Physik A Hadrons and Nuclei》1982,306(1):67-71
Electric quadrupole transition strengths for the 2 1 + ,T=1→0 1 + ,T=1γ-decay branches are summarized for 10≦A≦42 nuclei. In10B the corresponding branch has been remeasured by use of the9Be(p, γ)10B resonance reaction atE p =320 keV; an upper limit of 0.6% is found. The variation of theE2 strengths within each individualT=1 isobaric multiplet reveals the particleor hole-character of the levels involved. The isoscalar 2 1 + →0 1 + transition strengths in 10≦A≦48 nuclei vary between 2 and 20 Weißkopf units showing drastic shell effects. Results for the ratio of neutron and proton matrix elements deduced from analogγ-decay studies and from inelastic pion scattering are compared. 相似文献
17.
K P SANTHOSH 《Pramana》2011,76(3):431-440
Decay of neutron-deficient 128 − 137Gd parents emitting 4He to 32S clusters are studied within the Coulomb and proximity potential model. The predicted half-lives are compared with other
models and most of the values are well within the present experimental limit for measurements (T
1/2 < 1030 s). The lowest T
1/2 value for 28Si emission from 128Gd indicates the role of doubly magic 100Sn daughter in cluster decay process. It is also found that neutron excess in the parent nuclei slows down the cluster decay
process. Geiger–Nuttal plots for all clusters are found to be linear with different slopes and intercepts. The α-decay half-lives of 148 − 152Gd parents are computed and are in agreement with experimental data. The role of doubly magic 132Sn daughter in cluster decay process is also examined for various neutron-rich Ba, Ce, Nd, Sm and Gd parents emitting clusters
ranging from 4He to 32Si. Alpha-like structures are most probable in the decays leading to 100Sn, while non-α-like structures are probable in the decays leading to 132Sn. The neutron–proton asymmetry in parent and daughter nuclei is responsible for the reduced decay rate in the decay leading
to 132Sn. 相似文献
18.
T. Faestermann R. Schneider A. Stolz K. Sümmerer E. Wefers J. Friese H. Geissel M. Hellström P. Kienle H.-J. Körner M. Mineva M. Münch G. Münzenberg C. Schlegel K. Schmidt P. Thirolf H. Weick K. Zeitelhack 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):185-188
Neutron deficient nuclei near 100Sn have been produced by fragmentation of a 1 .
AGeV 112Sn beam. The fragments were separated, identified and stopped in a highly segmented silicon strip detector stack. This detector
measured the total energy of emitted β+-particles. γ-radiation was measured with surrounding detectors. The half-lives for many nuclides have been determined for
the first time and give important information for the following topics: For the heaviest particle-stable odd-odd nuclei 90Rh, 94Ag and 98In we observed for the first time fast β-decays, compatible with superallowed Fermi transitions and confirmed such decays
for 78Y, 82Nb and 86Tc. We have also observed long-lived T = 0 states in some of these nuclei. We measured the half-lives of all rp-process waiting-point nuclei from 80Zr up to 92, 93Pd. In addition we find the proton drip line nucleus 77Y to decay dominantly via β-decay. To study the Gamov-Teller strength in the β-decay near the doubly magic 100Sn we measured the half-life, β- and γ-spectrum of 102Sn. We propose a level scheme for the daughter nuclide 102In and deduce the Gamov-Teller strength (B
GT = 4.0±0.6). This is one of the largest values known.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: thomas.faestermann@ph.tum.de 相似文献
19.
Y. Fujita H. Fujita T. Adachi G.P.A. Berg E. Caurier H. Fujimura K. Hara K. Hatanaka Z. Janas J. Kamiya T. Kawabata K. Langanke G. Martınez-Pinedo T. Noro E. Roeckl Y. Shimbara T. Shinada S.Y. van der Werf M. Yoshifuku M. Yosoi R.G.T. Zegers 《The European Physical Journal A - Hadrons and Nuclei》2002,13(4):411-418
Under the assumption that isospin is a good quantum number, symmetry is expected for the transitions from the ground states
of T = 1, T
z = ±1 nuclei to the common excited states of the T
z = 0 nucleus situated between the two nuclei. The symmetry can be studied by comparing the strengths of Gamow-Teller (GT)
transitions obtained from a (p, n)-type charge-exchange reaction on a target nucleus with T
z = 1 with those from the β-decay of the T
z = - 1 nucleus. The A = 58 system is the heaviest for which such a comparison is possible. As a part of the symmetry study, we measured the GT
transitions from 58Ni (T
z = 1) to 58Cu (T
z = 0) by using the zero-degree (3
He, t) reaction at 150 MeV/nucleon. With the achieved resolution of 50 keV, many hitherto unresolved GT states have been identified.
The GT transition strengths were obtained for states up to 8 MeV excitation, i.e., near to the Q window limitation ( Q
EC = 9.37 MeV) of the β-decay from 58Zn (T
z = - 1) to 58Cu. The strength distribution is compared with that from shell-model calculations.
Received: 24 November 2001 / Accepted: 30 January 2002 相似文献
20.
Joachim JÄnecke 《Zeitschrift für Physik A Hadrons and Nuclei》1966,196(5):477-485
A new type of plot for the Coulomb energy differences between isobaric analogue states of neighboring isobaric nuclei withT z =T?1 andT z =T is introduced. The available experimental data when displayed in this form reveal nuclear structure effects. 相似文献