Band-crossing phenomena in 167, 168Hf and 170, 171W

doi:10.1016/0375-9474(83)90364-0

Nuclear Physics A

Volume 401, Issue 3, 13 June 1983, Pages 531-556

https://doi.org/10.1016/0375-9474(83)90364-0 Get rights and content

Abstract

High-spin states in ^167,168Hf and ^{170, 171}W have been excited by the reactions $^{159} Tb (^{14} N, x n)^{173 − x} Hf and^{155} Gd (^{20} Ne, x n)^{175 − x} W$ . The yrast bands have been observed up to $J^{π} = 492^{+}$ in ¹⁶⁷Hf, J^π = 28⁺ in ¹⁶⁸Hf, $J^{π} = 452^{+}$ in ¹⁷¹W and J^π = 22⁺ in ¹⁷⁰W. Both even-even nuclei display a strong backbend around J^π = 14⁺, whereas ¹⁶⁷Hf shows an upbend at ω ∼- 0.33 MeV and ¹⁷¹W exhibits a progressive gain in aligned angular momentum above ω ∼- 0.26 MeV. At even higher rotational frequencies, bridges have been found in the central valleys of the γ-γ correlation matrices at ω ∼- 0.42 and 0.52 MeV for the Hf isotopes and ω ∼- 0.45 and 0.47 MeV for the W isotopes. Deduced moments of inertia for the Hf isotopes using the correlation data show a smooth increase up to about the rigid-sphere value at ω ∼- 0.5 MeV. The data are satisfactorily accounted for by cranked shell-model calculations. In particular, a qualitative interpretation is given for the experimentally observed systematic difference in the strength of the interaction potential for the N = 95 and N = 97 isotopes of Hf and W.

References (32)

L.L. Riedinger
Nucl. Phys.
(1980)
Phys. Scripta
(1981)
P.M. Walker et al.
J. of Phys.
(1976)
R.V.F. Janssens et al.
Phys. Lett.
(1981)
M.J.A. de Voigt et al.
Phys. Lett.
(1981)
H.J.M. Aarts et al.
Nucl. Instr.
(1980)
H. F. R. Arciszewski, to be...
L.L. Riedinger et al.
ORNL Phys. Div. Ann. Progress Report 1973, ORNL-4937
(1974)
J.D. Garrett et al.
Phys. Rev. Lett.
(1981)
J. Bacelar et al.
Schuster Laboratory Annual Report
(1982)
I.Y. Lee et al.
Phys. Rev. Lett.
(1977)

F.A. Beck et al.

Phys. Rev. Lett.

(1979)

T. Byrski et al.

J. de Phys.

(1980)

J.C. Merdinger

Phys. Scripta

(1981)

R.M. Lieder et al.

Z. Phys.

(1972)

B. Bochev et al.

Nucl. Phys.

(1977)

C. Michel et al.

Verhandl. DPG

(1979)

C. Michel et al.

Z. Phys.

(1980)

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^†: Present address: Sterrekundig Instituut, Rijksuniversiteit Leiden, The Netherlands.

^††: Present address: Argone National Laboratory, Argone, Ill., USA.

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Band-crossing phenomena in 167, 168Hf and 170, 171W

Abstract

Nucl. Phys.

Phys. Scripta

J. of Phys.

Phys. Lett.

Phys. Lett.

Nucl. Instr.

ORNL Phys. Div. Ann. Progress Report 1973, ORNL-4937

Phys. Rev. Lett.

Schuster Laboratory Annual Report

Phys. Rev. Lett.

Phys. Rev. Lett.

J. de Phys.

Phys. Scripta

Z. Phys.

Nucl. Phys.

Verhandl. DPG

Z. Phys.

Band-crossing phenomena in ^{167, 168}Hf and ^{170, 171}W