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1.
Tumpa Bhattacharjee 《Pramana》2010,75(1):25-38
The variety of shapes and structures, observed in light rare earth A ∼ 130 nuclei, have been discussed in view of different angular momentum coupling schemes and their interplay that comes into
effect at high spin. The N = 79 and 80 isotopes in La-Ce region, produced via fusion evaporation reaction, have been studied using the Indian National
Gamma Array (INGA) consisting of 18 clover HPGe detectors. Two nearly degenerate ΔI = 1 bands have been observed at high spin of 137Ce and a triaxial deformation of γ = ±30° has been assigned to the bands, from the total Routhian surface (TRS) calculations. The high-spin candidates of the
yrast band of 138Ce show signature splitting both in energy and B(M1)/B(E2) values. The bandcrossing due to the alignment of a pair of h
11/2 proton particles has been conjectured at ℏω ∼ 0.3 MeV, from the single-particle Routhians obtained from TRS calculations. Lifetime measurements by Doppler shift attenuation
method (DSAM) has been carried out and from the estimated reduced transition probability B(M1), the ΔI = 1 band in 138Ce has been characterized as a magnetic rotation (MR) band. The rise in the values of B(M1), for the higher spin candidates of the band, has been conjectured as the reopening of a different shear at the top of the
Band B1. The characteristic of the MR bands in A ∼ 130 region has been discussed in the light of a phenomenological calculation and compared to the MR bands in other mass
regions. 相似文献
2.
C. S. Lee J. H. Ha J. H. Lee J. Y. Huh J. C. Kim C. -B. Moon S. J. Chae T. Komatsubara T. Shizuma H. Kimura K. Matsuura K. Kato Y. Sasaki H. Ishiyama K. Furuno 《The European Physical Journal A - Hadrons and Nuclei》2000,8(1):1-3
High-Spin states of odd-odd 166Lu were populated using the 139La(30Si,3nγ)166Lu at a beam energy of 120 MeV. Twelve new γ-rays were placed on top of the previously known two rotational bands built upon πg
7/2⊗νi
13/2 and πh
11/2⊗νi
13/2. Extending high-spin states up to 21+ and 25− for each band, we have observed the onset of band crossing near ħω
c ≈ 0.35 MeV. The band crossing frequency of the yrast πh
11/2⊗νi
13/2 band is consistent with the neutron BC band crossing observed in lighter odd-odd Lu isotopes. 相似文献
3.
J. Timár A. Gizon P. Paris J. Genevey J. Gizon F. Hannachi C.F. Liang A. Lopez-Martens J.C. Merdinger B.M. Nyakó B. Weiss L. Zolnai 《The European Physical Journal A - Hadrons and Nuclei》2000,7(1):7-10
High spin states of 126La have been populated using the reaction 116Sn+14N at 68 MeV. γ-rays and conversion electrons were detected with the GAREL array. Multipolarities of the lowest-lying in-band
dipole transitions have been determined from the deduced internal conversion coefficients. Experimental B(M1)/B(E2) ratios
have been derived for the bands and compared with calculated values using the D?nau-Frauendorf geometrical model. Configurations
are proposed for the bands comparing them with cranked shell model calculations and on the basis of the measured B(M1)/B(E2)
ratios. The β-decay of 126La has also been revisited. The population of the 126Ba levels gives a probable spin value of five for the decaying high-spin 126La state with T
1/2≈ 64 s which may indicate a signature inversion in the πh11/2νh11/2 band.
Received: 12 October 1999 相似文献
4.
T. Bäck B. Cederwall K. Lagergren R. Wyss A. Johnson P. Greenlees D. Jenkins P. Jones D.T. Joss R. Julin S. Juutinen A. Keenan H. Kettunen P. Kuusiniemi M. Leino A.-P. Leppänen M. Muikku P. Nieminen J. Pakarinen P. Rahkila J. Uusitalo 《The European Physical Journal A - Hadrons and Nuclei》2003,17(1):1-5
The decay out of the πh
11/2νh
11/2 band to the known low-energy levels in 132La was studied using the reaction 100Mo + 36S at 160 MeV beam energy. The low-energy level scheme has been further developed and unambiguous spin and parity values have
been assigned to the levels connecting the band to the 6- isomeric state. According to the new level scheme the spins in the πh
11/2νh
11/2 band are shifted up by one unit compared to the earlier tentative experimental values. The obtained new spins prove the existence
of signature inversion in 132La and give further support to the spin assignments made for the πh
11/2νh
11/2 bands in the neighbouring odd-odd La isotopes from level energy systematics.
Received: 7 May 2002 / Accepted: 31 October 2002 / Published online: 17 January 2003
RID="a"
ID="a"e-mail: timar@atomki.hu
RID="b"
ID="b"Present address: Dipartimento di Matematica e Fisica, Università di Camerino, via Madonna delle Carceri, I-62032 Camerino, Italy.
Communicated by J. ?yst? 相似文献
5.
R.P. Singh R.K. Bhowmik S.S. Ghugre S.B. Patel 《The European Physical Journal A - Hadrons and Nuclei》2000,7(1):35-40
High spins states in 99Rh were populated via the 66Zn(37Cl, 2p2n)99Rh reaction at an incident beam energy of 130 MeV. Seventeen new transitions have been observed in the present study and the
level scheme has now been extended up to a spin of J∼ 25ħ and an excitation energy of about E
x∼ 10 MeV. The observation of a positive parity E2 cascade based on the 9/2+ isomeric level is suggestive of collective behaviour in this nucleus up to high spins. Spherical shell model (within restricted
model space) and Cranked shell model calculations were performed to obtain an insight into the observed level structure. The
new collective band observed up to a spin of J∼ 25ħ is suggested to be based on (πg
9/2
3) ⊗ (νg
7/2
2) quasi-particle excitations.
Received: 12 July 1999 / Revised version: 14 September 1999 相似文献
6.
M. -G. Porquet Ts. Venkova A. Astier I. Deloncle A. Prévost F. Azaiez A. Buta D. Curien O. Dorvaux G. Duchêne B. J. P. Gall F. Khalfallah I. Piqueras M. Rousseau M. Meyer N. Redon O. Stézowski R. Lucas A. Bogachev 《The European Physical Journal A - Hadrons and Nuclei》2006,28(2):153-159
The 87Kr nucleus has been produced as fission fragment in the fusion reaction 18O + 208Pb at 85MeV bombarding energy and studied with the Euroball IV array. High-spin states of this neutron-rich isotope have been
identified for the first time. Its level scheme has been obtained up to 6.3MeV excitation energy and spin I ∼ 23/2ℏ. Its structure is interpreted by analogy with those of the heavier isotones. The proposed configurations involve
both proton and neutron excitations from several sub-shells located close to the Fermi levels, particularly νd5/2, πp3/2f5/2 and πg9/2. Moreover, a revised spin value of 5/2- for the 87Br ground state is proposed. 相似文献
7.
K. Singh S. Sihotra S. S. Malik J. Goswamy D. Mehta N. Singh R. Kumar R. P. Singh S. Muralithar E. S. Paul J. A. Sheikh C. R. Praharaj 《The European Physical Journal A - Hadrons and Nuclei》2006,27(3):321-324
The collective band structures of the 125Cs nucleus have been investigated by in-beam γ-ray spectroscopic techniques following the 110Pd ( 19F, 4n) reaction at 75MeV. The previously known level scheme, with rotational bands built on πg7/2, πg9/2 and πh11/2 orbitals, has been extended and evolves into bands involving rotationally aligned ν(h11/2)2 and π(h11/2)2 quasiparticles. A strongly coupled band has been reassigned a high-K πh11/2 ⊗ νg7/2 ⊗ νh11/2 three-quasiparticle configuration and a new side band likely to be its chiral partner has been identified. Configurations
assigned to various bands are discussed in the framework of Principal/Tilted Axis Cranking (PAC/TAC) model calculations. 相似文献
8.
X. L. Che S. J. Zhu M. L. Li Y. J. Chen Y. N. U H. B. Ding L. H. Zhu X. G. Wu G. S. Li C. Y. He Y. Liu 《The European Physical Journal A - Hadrons and Nuclei》2006,30(2):347-350
High-spin states in the 135Ba nucleus have been studied with the reaction 130Te(9Be, 4n) at a beam energy of 45 MeV. The level scheme based on the h
11/2 isomer has been expanded with spins up to 35/2 ℏ. At low spins, the yrast collective structure built on the ν h
11/2
-1 multiplet may show a transitional shape with γ > 30° according to the systematical behavior observed in neighboring nuclei as well as the calculations of the triaxial rotor-plus-particle
model. The configurations for several high-spin states have been discussed from a systematical comparison with neighboring
isotones. 相似文献
9.
R.S. Chakrawarthy B.S. Nara Singh R.G. Pillay 《The European Physical Journal A - Hadrons and Nuclei》1998,3(1):5-8
High spin states in 108In have been established upto ∼ 8 MeV in excitation energy and to a tentative spin of (23−). The data were obtained by in-beam γ-ray spectroscopy using the reaction 93Nb(19F, p3n)108In at a beam energy of 86 MeV. Four sequences of dipole bands and a normal rotational band of E2 γ-transitions have been placed
in the level scheme.
Received: 16 June 1998 相似文献
10.
C.-B. Moon T. Komatsubara Y. Sasaki T. Jumatsu K. Yamada K. Satou K. Furuno 《The European Physical Journal A - Hadrons and Nuclei》2002,14(1):13-16
Excited states of the 119Xe nucleus have been studied by using in-beam γ-ray spectroscopy with the 107Ag ( 16O, p3n) 119Xe fusion-evaporation reaction at a beam energy of 85 MeV. The level scheme of 119Xe has been derived from γ-γ coincidence and γ-γ angular correlation analyses. We have, for the first time, established the
second negative-parity favored and unfavored states built on the 11/2- state, namely the yrare rotational bands in 119Xe. In contrast to the behavior of the yrast bands where the favored states are lying lower in energy, the yrare favored states
were observed to lie above the unfavored band. Such a signature inversion in 119Xe is changed to be normal at I = 12?.
Received: 8 January 2002 / Accepted: 18 April 2002 相似文献
11.
L. Batist M. Górska H. Grawe Z. Janas M. Kavatsyuk M. Karny R. Kirchner M. La Commara I. Mukha A. Plochocki E. Roeckl 《The European Physical Journal A - Hadrons and Nuclei》2010,43(1):45-53
Excited states of the 49107In nucleus were populated through the 78Se ( 32S , p2n) fusion-evaporation reaction at beam energy, E
lab = 125 MeV. The de-excitations were studied using in-beam g \gamma -ray spectroscopic techniques involving the Compton-suppressed clover detector array. The level scheme of 107In consisting of about seven bands is established up to spin ∼ 45/2ℏ with the addition of 25 new transitions. Spins and parities
of various levels have been assigned through the DCO and polarization measurements. The level structures observed in 107In have been interpreted in the framework of a microscopic theory based on the deformed Hartree-Fock (HF) and angular-momentum
projection techniques. Various bands are reproduced in band mixing calculations with the configurations involving high-W \Omega
p \pi
g
9/2 and n \nu
d
5/2 orbits, and low-W \Omega
p \pi
g
7/2 , n \nu
g
7/2 and n \nu
h
11/2 orbits. 相似文献
12.
High-spin states of 136La have been investigated with the reaction 130Te( 11B, 5n) at a beam energy of 60 MeV. The level scheme with three collective bands has been updated with spin up to 20 . The observed h11/2 h11/2 band shows -instability with increasing spin according to the TRS calculations. The band crossing and the signature splitting and inversion have been discussed. Other two collective bands based on 12-and 16+ levels were proposed as oblate deformation with -60°. They most probably originate from four- and six-quasiparticle configurations, that is, h11/2 g7/2h11/22 and g7/2 g7/22d5/2h11/22 respectively. 相似文献
13.
X. H. Zhou L. Ma Y. B. Xing Y. H. Zhang Y. X. Guo X. G. Lei C. Y. Xie M. Oshima Y. Toh M. Koizumi A. Osa Y. Hatsukawa M. Sugawara M. M. Ndontchueng 《The European Physical Journal A - Hadrons and Nuclei》2006,28(3):271-275
Excited states in 188Tl have been studied experimentally using the 157Gd (35Cl, 4n) reaction at a beam energy of 170MeV. A rotational band built on the πh
9/2 ⊗ νi
13/2 configuration with oblate deformation has been established for 188Tl. Based on the structure systematics of the oblate πh
9/2 ⊗ νi
13/2 bands in the heavier odd-odd Tl nuclei, we have tentatively proposed spin values for the new band in 188Tl. The πh
9/2 ⊗ νi
13/2 oblate band in 188Tl shows low-spin signature inversion, and it can be interpreted qualitatively by the two-quasiparticle plus rotor model including
a J-dependent p-n residual interaction. 相似文献
14.
Y.-J. Ma Y.-Z. Liu H.-B. Sun S. Wen S.-G. Zhou H. Zheng H.-T. Yang J.-D. Huo X.-G. Wu C.-X. Yang 《The European Physical Journal A - Hadrons and Nuclei》1998,2(1):21-23
Three new bands in 174Ta have been identified by using the 160Gd(19F,5n) reaction at beam energies of 87 MeV and 96 MeV. Nilsson configurations are assigned to these bands. In the 9/2−[514]p+5/2−[512]n band, the AB neutron crossing occurs at a rotational frequency of 0.30 MeV. This is indicative of the disappearance of the
evidence for a reduction in neutron pair correlations.
Received: 30 March 1998 相似文献
15.
E. O. Lieder A. A. Pasternak R. M. Lieder A. D. Efimov V. M. Mikhajlov B. G. Carlsson I. Ragnarsson W. Gast Ts. Venkova T. Morek S. Chmel G. de Angelis D. R. Napoli A. Gadea D. Bazzacco R. Menegazzo S. Lunardi W. Urban Ch. Droste T. Rzaca-Urban G. Duchêne A. Dewald 《The European Physical Journal A - Hadrons and Nuclei》2008,35(2):135-158
For a level scheme investigation of 142Gd an experiment with the γ -spectrometer EUROBALLIII has been carried out and lifetimes have been measured with EUROBALL
IV using the Doppler-shift attenuation method. The high-spin states have been populated in these experiments by means of the
99Ru(48Ti, 2p3n) reaction at a beam energy of 240MeV and the 114Sn(32S, 2p2n) reaction at 160MeV, respectively. Reduced E2 transition probabilities B(E2) were determined for 15 members of four quadrupole bands. For the interpretation of the positive-parity even-spin quadrupole
bands, calculations in the cranked Nilsson-Strutinsky as well as interacting boson models have been performed. From the former
calculations it was concluded that the high-spin states of the (+ , 0)1 band in 142Gd represent a triaxial nucleus rotating around the longest principal axis. 相似文献
16.
M. Wolińska-Cichocka J. Kownacki W. Urban E. Ruchowska W. A. Płóciennik B. Bekman Ch. Droste W. Gast R. Lieder W. Meczyński M. Kisieliński A. Kordyasz M. Kowalczyk P. Kowina J. Iwanicki T. Morek J. Perkowski J. Srebrny A. Stolarz J. Styczeń 《The European Physical Journal A - Hadrons and Nuclei》2005,24(2):259-274
Excited states in 110Sn and 111Sn nuclei have been investigated using in-beam -ray spectroscopic methods. An 16O beam with an energy of 60-80MeV was used to bombard a 98Mo target. On the basis of the relative excitation functions, -ray angular distributions, - and -time distributions, -ray multiplicity and total energy data, the level schemes of 110Sn and 111Sn have been studied and extended up to Eexc 11.5MeV, I = 24, and Eexc 11.1MeV and I = (51/2), respectively. An extension of the intruder, g.s. and negative-parity bands, as well as 5 new band-like structures are proposed in 110Sn. The nature of newly introduced collective band 8 as well as 10+ states fed in the decay of the collective band is discussed. In the 111Sn nucleus an intruder band based on the 23/2- state has been reinvestigated and the extension of the g.s. band and second negative-parity band is given. Evidence for neutron-core coupling in 111Sn is found. The structure and systematics of excited states in light Sn isotopes is discussed. 相似文献
17.
R.M. Lieder T. Rzaca-Urban H. Brands W. Gast H.M. Jäger L. Mihailescu Z. Marcinkowska W. Urban T. Morek Ch. Droste P. Szymański S. Chmel D. Bazzacco G. Falconi R. Menegazzo S. Lunardi C. Rossi Alvarez G. de Angelis E. Farnea A. Gadea D.R. Napoli Z. Podolyak Ts. Venkova R. Wyss 《The European Physical Journal A - Hadrons and Nuclei》2002,13(3):297-305
High-spin states in 142Gd have been populated by means of the 99Ru(48Ti, 2p3n) reaction at 240 MeV and investigated with the γ-spectrometer EUROBALL III and the charged-particle detector array
ISIS. The features of four dipole bands have been determined and compared with tilted-axis cranking model calculations indicating
that they are magnetic rotational bands. A transition from regular to irregular bands has been found approaching N = 82 demonstrating that this is a general phenomenon in nuclei near a double-shell closure.
Received: 9 December 2001 / Accepted: 9 January 2002 相似文献
18.
T.R. Saitoh N. Hashimoto G. Sletten R.A. Bark S. Törmänen M. Bergström K. Furuno K. Furutaka G.B. Hagemann T. Hayakawa T. Komatsubara A. Maj S. Mitarai M. Oshima J. Sampson T. Shizuma P.G. Varmette 《The European Physical Journal A - Hadrons and Nuclei》1998,3(3):197-199
High-spin states in 181Ta have been studied via the 176Yb(11B,α2n) reaction at 52 MeV using the PEX array and at 57 MeV using the NORDBALL array, with α-particle detection. The previously
known, Kπ=(7/2)+ ground state band and Kπ=(9/2)− band have been extended to spins (29/2)+ and (31/2)−, respectively. Two new one-quasiparticle bands, the Kπ=(5/2)+ band built on the known (5/2)+ isomer and a Kπ=((1/2)−) band have been observed. Two other rotational bands with three-quasiparticle structure, Kπ=(15/2)− and ((19/2)+ with π(7/2)[404]ν2(1/2)[510](9/2)[624] and π(9/2)[514]ν2(1/2)[510](9/2)[624] configurations, respectively, have been newly observed. The half-life of the Kπ=((19/2)+) bandhead which decays to the head of the (15/2)− band has been measured to be 140(36) ns. However, transitions from the ((19/2)+) state to the (15/2)− band have not been observed.
Received: 26 August 1998 相似文献
19.
Vinod Kumar Pragya Das R.P. Singh S. Muralithar R.K. Bhowmik 《The European Physical Journal A - Hadrons and Nuclei》2003,17(2):153-157
The fusion evaporation reaction 122Sn(14N, 4n)132La was used to populate the high-spin states of 132La at the beam energy of 60 MeV. A new band consisting of mostly E2 transitions has been discovered. This band has the interesting links to the ground state 2- and the isomeric state 6-. A new transition of energy 351 keV connecting the low-spin states of the positive-parity band based on the πh
11/2 ⊗ νh
11/2 particle configuration, has been found. This has played a very important role in resolving the existing ambiguities and inconsistencies
in the spin assignment of the band head.
Received: 12 August 2002 / Accepted: 18 March 2003 / Published online: 7 May 2003 相似文献
20.
M. Fantuzi C. M. Petrache D. Mengoni M. Axiotis D. Bazzacco G. Benzoni P. G. Bizzeti A. M. Bizzeti-Sona N. Blasi A. Bracco G. de Angelis E. Farnea A. Gadea Th. Kröll S. Leoni H. L. Liu S. Lunardi N. Marginean R. Menegazzo D. R. Napoli M. Nespolo P. Pavan C. Rossi Alvarez P. Spolaore C. A. Ur R. Venturelli F. R. Xu 《The European Physical Journal A - Hadrons and Nuclei》2008,38(1):43-51
Excited states in the very neutron-deficient122La nucleus have been established for the first time using the92Mo(40Ca, 2α1p1n) reaction at beam energies of 190 and 200MeV. The observed transitions were grouped in three bands. Configurations have been
assigned to the observed bands based on the properties extracted from the experimental data and on cranked shell model calculations. 相似文献