Coulomb Excitation of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">Si</mml:mi></mml:mrow><mml:mprescripts /><mml:mrow /><mml:mrow><mml:mn>28</mml:mn></mml:mrow><mml:mrow /><mml:mrow /></mml:mmultiscripts></mml:mrow></mml:math>Projectiles

Häusser, O.; Alexander, T.K.; Pelte, D.; Hooton, B.W.; Evans, H. C.

doi:10.1103/physrevlett.23.320

Cited by 70 publications

(40 citation statements)

References 13 publications

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“…However, to summarize the most important points of that discussion we note, (1) there are several experimental investigations which strongly indicate that the intrinsic shape of~Mg is prolate and axial while HF unambiguously predicts the shape to be triaxial, (2) for "Si, HF. predicts both a low-lying oblate and an orthogonal low-lying prolate intrinsic state which is in contradiction to the experimental spectrum, (3) for "S, HF predicts a triaxial shape' with P, = 0 again in contradiction to the experimental spectrum, and (4) experiments suggest that "Ar can be interpreted phenomenologically as a vibrator, while HF predicts a well-deformed oblate intrinsic state giving low-ener gy rotational levels. Thus, if we are able to adopt the concept of an intrinsic state, then a more complicated one must be used.…”

Section: Introductionmentioning

confidence: 57%

Generalized Pairing in Light Nuclei. II. Solution of the Hartree-Fock-Bogoliubov Equations with Realistic Forces and Comparison of Different Approximations

et al. 1970

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The Hartree-Fock-Bogoliubov (HFB) equations with generalized isospin pairing are numerically solved without any approximations, except imposing certain self-consistent symmetries. Realistic forces are used to make definite conclusions concerning the shapes of nuclei and the existence of isospin pairing. Comparison with previous approximations shows that in the s-d shell the HFB equations may not be quantitatively approximated by HF+ BCS, HB -BCS, or by iterating between HF and BCS. Isospin pairing offers an explanation for axial symmetry in Mg and 'S and for the existence of low-lying vibrational states in Ar.

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Section: Introductionmentioning

confidence: 57%

Generalized Pairing in Light Nuclei. II. Solution of the Hartree-Fock-Bogoliubov Equations with Realistic Forces and Comparison of Different Approximations

et al. 1970

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“…There is shape coexistence between the oblate ground-state band and a prolate (normal-deformed or ND) band, in conformity with the known band structure of 28 Si. The ground state band was identified up to J = 8 by Ford et al [18], and its oblate nature was demonstrated through Coulomb excitation measurements performed by Häusser et al [19]. An excited rotational band whose bandhead lies at 6.691 MeV, was identified 30 years ago by Glatz et al [20], and is assumed to correspond to the prolate (ND) band.…”

Section: Introductionmentioning

confidence: 99%

Candidate superdeformed band in28Si

et al. 2012

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Recent antisymmetrized molecular dynamics (AMD) calculations for28 Si suggest the presence of a superdeformed (SD) band with a dominant 24 Mg+α clustering for its configuration, with firm predictions for its location and associated moment of inertia. This motivates a review of the experimental results reported in the literature with a particular focus on 24 Mg(α,γ) studies, as well as on alpha-like heavy-ion transfer reactions such as 12 C( 20 Ne,α) 28 Si. Combining this information for the first time, leads to a set of candidate SD states whose properties point to their alpha-cluster structure and strong associated deformation. Analysis of data from Gammasphere allows the electromagnetic decay of these candidate states to be probed and reveals further supporting evidence for such a structure. This paper appraises this body of information and finds the evidence for an SD band is strong.

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“…An answer may be obtained by making use of the reorientation effect in lowenergy Coulomb excitation to infer shapes. This technique has been used in tracing transitions from prolate to oblate deformation across the middle of the sd shell (revealing the oblate shape of 28 Si [18]) and more recently investigating deformed intruder states in 70 Ge [19]. With the advent of relatively intense radioactive-ion beams, this method can now be used to probe the structure of nuclei far from stability.…”

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confidence: 99%

Measurement of the Sign of the Spectroscopic Quadrupole Moment for the21+State inSe70: No Evidence for Oblate Shape

Hurst¹,

Butler²,

Jenkins³

et al. 2007

Phys. Rev. Lett.

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Using a method whereby molecular and atomic ions are independently selected, an isobarically pure beam of 70 Se ions was postaccelerated to an energy of 206 MeV using REX-ISOLDE. Coulomb-excitation yields for states in the beam and target nuclei were deduced by recording deexcitation rays in the highly segmented MINIBALL -ray spectrometer in coincidence with scattered particles in a silicon detector. At these energies, the Coulomb-excitation yield for the first 2 state is expected to be strongly sensitive to the sign of the spectroscopic quadrupole moment through the nuclear reorientation effect. Experimental evidence is presented here for a prolate shape for the first 2 state in 70 Se, reopening the question over whether there are, as reported earlier, deformed oblate shapes near to the ground state in the light selenium isotopes. DOI: 10.1103/PhysRevLett.98.072501 PACS numbers: 21.10.Ky, 25.70.De, 27.50.+e A remarkable property of the nucleus is its ability to assume different configurations giving energy minima corresponding to different shapes of the mean field. It is often claimed that the presence of low-lying excited 0 states in even-even nuclei is strong evidence for such shape coexistence, since it is difficult to account for the presence of such states otherwise [1,2]. Arguably the most striking example of this is the case of 186 Pb [3], where both the first and second excited states have a spin parity of 0 . These states were interpreted as the bandheads of oblate and prolate rotational configurations, in close competition with the spherical ground state expected for this singly magic (Z 82) nuclear system. The region close to the N Z line from 56 Ni to 80 Zr is believed to be one of rapidly changing nuclear shape. At the upper end of this region, strongly prolate deformed shapes are found: 80 Zr is suggested to have 2 0:4 on the basis of the high moment of inertia [4], and a strongly prolate ground state, consistent with 2 0:4, has recently been established from the Gamow-Teller strength distribution in 76 Sr [5]. For the midshell nuclei near N Z 34 and 36, large shell gaps exist for protons and neutrons at both prolate and oblate shape, which would favor shape coexistence near the ground state. In the light krypton isotopes, 72-78 Kr, a low-lying excited 0 state is observed. There is good experimental evidence that this state has an oblate intruder configuration, and it most likely becomes the ground state in 72 Kr [6,7]. An analysis of the mixing of this state with the ground state, through consideration of their perturbed energies and the excited state lifetime, suggests an oblate ground state for 72 Kr [6], while the recently measured BE2; 0 ! 2 value in this nucleus, PRL 98,

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Coulomb Excitation ofSi28Projectiles

Cited by 70 publications

References 13 publications

Generalized Pairing in Light Nuclei. II. Solution of the Hartree-Fock-Bogoliubov Equations with Realistic Forces and Comparison of Different Approximations

Generalized Pairing in Light Nuclei. II. Solution of the Hartree-Fock-Bogoliubov Equations with Realistic Forces and Comparison of Different Approximations

Candidate superdeformed band in28Si

Measurement of the Sign of the Spectroscopic Quadrupole Moment for the21+State inSe70: No Evidence for Oblate Shape

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