New Iπ = 0+ states below 2 MeV in 166Er

doi:10.1016/0375-9474(92)91130-H

Nuclear Physics A

Volume 550, Issue 1, 30 November 1992, Pages 21-33

https://doi.org/10.1016/0375-9474(92)91130-H Get rights and content

Abstract

Levels in ¹⁶⁶Er have been studied with the ¹⁶⁴Er(t, p) and ¹⁶⁸Er(p, t) reactions using beams of 17 MeV tritons and 18 MeV protons. The reaction products were analysed with a magnetic spectrograph. I^π = 0⁺ levels populated in these reactions could be readily identified from the characteristic L = 0 angular distributions, and new 0⁺ states have been discovered at 1713 and 1935 keV. The previously known 1460 keV 0⁺ state and the one at 1713 keV are both strongly populated in the (t, p) reaction. Contrary to the findings of a previous study, the (p, t) reaction also has a large amount of L = 0 strength to excited states in ¹⁶⁶Er, in particular to the 1713, 1935 and 2196 keV levels. These results agree well with the systematics of two-neutron transfer strengths to excited 0⁺ states in this mass region.

References (22)

S. Yoshida
Nucl. Phys.
(1962)
D.G. Burke et al.
Nucl. Phys.
(1988)
M.A. Oothoudt et al.
Nucl. Phys.
(1973)
A.E. Ignatochkin et al.
Nucl. Data Sheets
(1987)
R.J. Ascuitto et al.
Nucl. Phys.
(1972)
Th.W. Elze et al.
Nucl. Phys.
(1972)
P.C. Sood et al.
At. Data Nucl. Data Tables
(1991)
R. Broglia et al.
D.G. Burke et al.
Can. J. Phys.
(1983)
M.H. Mortensen et al.
Phys. Rev.
(1980)

G. Løvhøiden et al.

Phys. Scr.

(1986)

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(t, p) reaction studies of 165Dy and 179Hf
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Angular distributions for the ¹⁶³Dy( $t, p$ ) and ¹⁷⁷Hf( $t, p$ ) reactions were measured using 17 MeV tritons from the McMaster University Tandem Van de Graaff accelerator. Reaction products were analyzed with a magnetic spectrograph and detected with photographic emulsions. Favored $L = 0$ transitions confirmed assignments of the $5 / 2^{-} [523]$ band in ¹⁶⁵Dy and $7 / 2^{-} [514]$ band in ¹⁷⁹Hf. Additional $L = 0$ transitions in each nuclide identified previously unknown $5 / 2^{-}$ levels in ¹⁶⁵Dy and $7 / 2^{-}$ ones in ¹⁷⁹Hf. Overall trends of $L = 0$ strengths support the existence of subshell closures at neutron numbers 98 and 108. On the basis of a relatively strong $L = 2$ transition, the $K^{π} = 11 / 2^{-}$ γ-vibration based on the $7 / 2^{-} [514]$ state is identified at 1689 keV in ¹⁷⁹Hf, about 440 keV above its previously-assigned $K^{π} = 3 / 2^{-}$ partner.
The nature of 0+ excitations in 166Er
1997, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Lifetimes of excited 0⁺ states in ¹⁶⁶Er have been measured with the (n,n′γ) reaction. The first and second excited 0⁺ states have no significant collective enhancements of their decays, and their properties are suggestive of pair-type excitations rather than those of a β vibration or phonon excitation built on the γ vibration. The third excited 0⁺ state at 1934 keV has an enhanced decay to the ground state band with B(E2; 0₄⁺ → 2_gsb⁺) = 8.8 ± 0.9 W.u., consistent with that expected for a β vibration.
Two-phonon γ-vibrational states in 166Er
1996, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
The nucleus ¹⁶⁶Er has been Coulomb excited using a beam of ⁵⁸Ni. In addition to the ground-and γ-vibrational bands three states were observed, a new state at 1943 keV, a previously known 4⁺ state at 1978 keV and a new state at 2029 keV suggested to have also spin and parity 4⁺. The two 4⁺ states decay to the 2⁺ and 3⁺ states of the one-phonon γ-vibrational band, and their B(E2) values to the 2_γ⁺ state are measured to 49₋₂₅⁺²⁰ and 267₋₁₀₀⁺¹⁰⁰ e² fm⁴, respectively. It is suggested that the 1978 keV state has a small and the 2029 keV state a large component of the K^π = 4⁺ two-phonon γ vibrational configuration in their wave functions.
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Nuclear Physics A

Abstract

References (22)

Nucl. Phys.

Nucl. Phys.

Nucl. Phys.

Nucl. Data Sheets

Nucl. Phys.

Nucl. Phys.

At. Data Nucl. Data Tables

Can. J. Phys.

Phys. Rev.

Phys. Scr.

Cited by (10)

(t, p) reaction studies of <sup>165</sup>Dy and <sup>179</sup>Hf

The nature of 0<sup>+</sup> excitations in <sup>166</sup>Er

Two-phonon γ-vibrational states in <sup>166</sup>Er

Characterization of the β vibration and 0<sup>+</sup><inf>2</inf> states in deformed nuclei

High-resolution study of Er 166 with the (p, t) reaction HIGH-RESOLUTION STUDY of Er 166 with the ... D. BUCURESCU et al.

First identification of large electric monopole strength in well-deformed rare earth nuclei