Deeply bound hole states and isobaric analog states in 89Zr

doi:10.1016/0375-9474(77)90131-2

Nuclear Physics A

Volume 288, Issue 2, 26 September 1977, Pages 221-241

https://doi.org/10.1016/0375-9474(77)90131-2 Get rights and content

Abstract

The ⁹⁰Zr(τ, α)⁸⁹Zr reaction, at 39 MeV incident energy, was used to populate hole states up to 13.5 MeV excitation energy in ⁸⁹Zr. A split-pole spectrometer was used for particle analysis and detection. In the excitation energy range between 0 and 3.5 MeV, about twenty well-resolved states were observed in ⁸⁹Zr, many for the first time. These states contain almost all of the spectroscopic strengths of the 1g_$92$, 2p_$12$, 2p_$32$ and 1f_$52$ neutron Subshells. The 30–35 keV energy resolution of the present study revealed a fine structure in the bump previously observed around 4.5 MeV and tentatively identified as the main part of the 1f_$72$. hole orbital. About thirty levels or groups of levels were excited between 3.5 and 7.0 MeV excitation energy and angular distributions have been extracted for each individual group as well as for the gross structure itself. A DWBA analysis of the data was carried out and shows that the main part of the observed fine structure is populated by l = 3 angular momentum transfer. The full sum rule strengths obtained for the states below 3.5 MeV for the pick-up of the 1g_$92$, 2p_$12$. 2p_$32$ and 1f_$52$ nucleon lead to the identification of this highly fragmented bump with the 1f_$72$ shell. We found between 50 to 70 % of the 1f_$72$ hole strength in this region. Four sharp and strongly excited peaks are observed at higher excitation energy (8–10 MeV) above a continuous background. They are identified with the known isobaric analog states of the first four excited levels in the ⁸⁹Y parent nucleus. Around 13 MeV a weakly excited peak is observed which has an l = 3 angular distribution. This level is proposed as the IAS of the first component of the 1f_$72$. proton hole orbital located around 5 MeV in ⁸⁹Y. In order to compare the spectroscopic strengths of the IAS and of their parent states, the neutron form factor has been calculated by solving the Lane coupled-channel equations. This method is shown to produce an overall agreement between the strengths of the parent analog pairs of levels.

References (22)

T. Ishimatsu
Nucl. Phys.
(1972)
M. Sakai
Phys. Lett.
(1974)
E. Gerlic et al.
Phys. Lett.
(1975)
M. Sekiguchi et al.
Nucl. Phys.
(1977)
G. Bassani et al.
Nucl. Phys.
(1969)
H. Taketani et al.
Nucl. Phys.
(1973)
S. Galès et al.
Nucl. Phys.
(1976)
D.C. Kocher
Nucl. Data Sheets
(1975)
J.R. Shepard et al.
Nucl. Phys.
(1977)
R. Stock et al.
Nucl. Phys.
(1967)

M. Sakai et al.

Nucl. Phys.

(1972)

Cited by (28)

Nuclear Data Sheets for A = 89
2013, Nuclear Data Sheets
The evaluated experimental data are presented for 14 known nuclides of mass 89 (Ge, As, Se, Br, Kr, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh). New data on high–spin excitations are available for ⁸⁹Kr, ⁸⁹Rb, ⁸⁹Sr, ⁸⁹Tc and ⁸⁹Ru, including a superdeformed structure in ⁸⁹Tc. Fluorescence studies in ⁸⁹Y have revealed a large number of new levels in 7–11 MeV range. New two–neutron transfer data are available for ⁸⁹Zr. New direct and precise measurement of atomic masses of ⁸⁹Se, ⁸⁹Br, 89^Kr, ⁸⁹Rb, ⁸⁹Mo and ⁸⁹Tc have greatly improved the Q value landscape in this mass region. This work supersedes previous A=89 evaluation published in 1998Si31, and also the older ones 1989Si20, 1975Ko21, and M.W. Johns et al., Nuclear Data Tables A 8, 373 (1970).
In spite of extensive experimental work on the isobaric nuclei of this mass chain several deficiencies remain. The identification of ⁸⁹Rh isotope remains unconfirmed. The half–lives of ground states of ⁸⁹Ge, ⁸⁹As and ⁸⁹Rh have not been measured, only the lower limits are estimated from time–of–flight in a reaction and experimental arrangement, where produced and identified. The decay schemes of ⁸⁹Ge, ⁸⁹As, ⁸⁹Se, ⁸⁹Ru and ⁸⁹Rh are not known, and those for ⁸⁹Tc and ⁸⁹Mo are incomplete. High–lying (neutron unbound) levels in ⁸⁹Kr, expected to be populated in the decay of ⁸⁹Br, have not been investigated. The spins and parities for levels in ⁸⁹Kr are largely unassigned, while for ⁸⁹Tc and ⁸⁹Ru, only few low–spin excitations are established. For ⁸⁹Rb, little information is available for high–spin structures. Detailed gamma–ray data are available for ⁸⁸Sr(n,γ)⁸⁹Sr reaction, but most of these γ rays remain unassigned in a level scheme. Excited state data are nonexistent for ⁸⁹Ge, ⁸⁹As, ⁸⁹Se, ⁸⁹Br and ⁸⁹Rh. The ⁸⁹Y and ⁸⁹Zr are the most extensively studied nuclei in A=89.
Structure of the 89Zr via the high-resolution 91Zr(p, t) 89Zr reaction and shell-model calculations
2002, Nuclear Physics A
The ⁹¹Zr(p, t)⁸⁹Zr reaction has been studied in a high-resolution experiment at an incident proton energy of 25 MeV. Angular distributions for transitions to 44 levels of ⁸⁹Zr up to an excitation energy of ∼ 3.650 MeV have been measured. DWBA analysis, with conventional Woods–Saxon potentials, allowed the assignment of the transferred angular momenta L. The energy spectrum of ⁸⁹Zr has been studied in the framework of the shell model, using the large-basis shell-model code OXBASH. The structure of both positive- and negative-parity states of ⁸⁹Zr has been investigated using the PMM90pn residual interaction, and discussed in comparison with the experimental findings from the ⁹¹Zr(p, t)⁸⁹Zr reaction.
Nuclear data sheets for A = 89
1998, Nuclear Data Sheets
The evaluated experimental data are presented for 14 known nuclides of mass 89 (Ge, As, Se, Br, Kr, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh). Excited state data are nonexistent for⁸⁹Ge,⁸⁹As,⁸⁹Se,⁸⁹Br,⁸⁹Ru, and⁸⁹Br. High-spin excitations are known for⁸⁹Sr,⁸⁹Y,⁸⁹Zr,⁸⁹Nb,⁸⁹Mo and⁸⁹Tc; neutron capture ;gg-ray data are available for⁸⁹Sr (neutrons at thermal energy); and particle-transfer data exist for⁸⁹Rb,⁸⁹Sr,⁸⁹Y,⁸⁹Nb and⁸⁹Mo. This work supersedes earlier A = 89 Nuclear Data Sheets (89Si20, 75Ko21).
Neutron decay of deep-hole states in 89Zr populated by the 90Zr(3He,α)89Zr reaction at 102 MeV
1995, Nuclear Physics, Section A
Neutron decay of excited hole states populated by the ⁹⁰Zr(³He,α) reaction at an incident energy of 102 MeV has been investigated. The α-particles were analysed in a magnetic spectrograph positioned at 1.4° and detected with a multi-wire drift chamber. Excitation energies in ⁸⁹Zr up to 26 MeV were studied. An array of neutron detectors was positioned around the target at angles ranging from 68° to 209°. The neutron data were analysed in terms of decay into final states, using statistical model calculations as a tool to extract non-statistical decay.
Hole strengths and spreading widths observed in 92Mo(p, d)91Mo reaction at 65 Me V
1993, Nuclear Physics, Section A
Differential cross sections and analyzing powers have been measured for the $^{92} Mo (p, d)^{91} Mo$ reaction with a polarized proton beam of 65 MeV incident energy for investigating the level structure of ⁹¹Mo up to 10 MeV. The data analysis with the standard DWBA theory provides transferred angular momenta lj values and spectroscopic factors for 42 transitions to the single-hole $1 g_{92}$ , $2 p_{12}$ , $2 p_{32}$ , $1 f_{52}$ and $1 f_{72}$ st analog states. The spreading widths are deduced and compared with theoretical predictions for discussing the damping mechanism of the single-hole states.
Nuclear data sheets for A = 89
1989, Nuclear Data Sheets

View all citing articles on Scopus

^†: Permanent address: Lebanese University, Faculty of Sciences, Hadat-Beyrouth, Lebanon.

View full text

Article preview

Nuclear Physics A

Abstract

References (22)

Nucl. Phys.

Phys. Lett.

Phys. Lett.

Nucl. Phys.

Nucl. Phys.

Nucl. Phys.

Nucl. Phys.

Nucl. Data Sheets

Nucl. Phys.

Nucl. Phys.

Nucl. Phys.

Cited by (28)

Nuclear Data Sheets for A = 89

Structure of the <sup>89</sup>Zr via the high-resolution <sup>91</sup>Zr(p, t) <sup>89</sup>Zr reaction and shell-model calculations

Nuclear data sheets for A = 89

Neutron decay of deep-hole states in <sup>89</sup>Zr populated by the <sup>90</sup>Zr(<sup>3</sup>He,α)<sup>89</sup>Zr reaction at 102 MeV

Hole strengths and spreading widths observed in <sup>92</sup>Mo(p, d)<sup>91</sup>Mo reaction at 65 Me V

Nuclear data sheets for A = 89