Decay properties of high-spin isomers and other structures in {sup 121}Sb and {sup 123}Sb
- Department of Nuclear Physics, Research School of Physical Sciences and Engineering, Australian National University Canberra, ACT 0200 (Australia)
- Nuclear Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
- Department of Physics, University of Massachusetts, Lowell, Massachusetts 01854 (United States)
- Department of Display Engineering, Hoseo University, Chung-Nam 336-795 (Korea, Republic of)
High-spin states populated in the decay of microsecond isomers in the transitional nuclei {sup 121}Sb and {sup 123}Sb have been investigated in detail in several experiments using {gamma}-ray and electron spectroscopy. The nuclei were formed using multinucleon transfer and fusion-fission reactions with {sup 136}Xe beams and also using the {sup 120}Sn({sup 7}Li,{alpha}2n){sup 121}Sb and {sup 122}Sn({sup 7}Li,{alpha}2n){sup 123}Sb incomplete-fusion reactions. Isomeric half-lives ranging from several nanoseconds to a few hundred microseconds were determined by means of conventional decay curve analyses, whereas very short-lived isomers (T{sub 1/2}{approx}1 ns) were identified using the generalized centroid-shift method. A number of new transitions were observed, including a branch through spherical states from the 19/2{sup +} member of the 9/2{sup +} deformed band in {sup 121}Sb, in competition with the main decay path through the rotational band. This is attributed to mixing between the 19/2{sup +} band member and a 19/2{sup +} spherical state. Both levels are predicted to coincide approximately in energy in {sup 121}Sb. The fact that a 25/2{sup +} isomer occurs for A=121 and the lighter isotopes, while a 23/2{sup +} isomer is observed for A=123-131 is explained through a multistate mixing calculation, taking into account the gradual shift of the 2d{sub 5/2} and 1g{sub 7/2} proton orbitals and the change in proton-neutron effective interactions from an attractive particle-particle type in the lower part of the shell to a repulsive particle-hole type with increasing the neutron number toward the N=82 shell closure. The observed enhancement of the B(E2;19/2{sup -}{yields}15/2{sup -}) values in {sup 121}Sb and {sup 123}Sb over the B(E2;7{sup -}{yields}5{sup -}) values in the corresponding Sn cores is discussed in terms of configuration mixing between spherical and deformed states.
- OSTI ID:
- 21202717
- Journal Information:
- Physical Review. C, Nuclear Physics, Vol. 79, Issue 2; Other Information: DOI: 10.1103/PhysRevC.79.024306; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
- Country of Publication:
- United States
- Language:
- English
Similar Records
High-spin, multi-particle isomers in {sup 121,123}Sb.
E2/Ml RATIOS IN THE ISOMERIC TRANSITIONS OF Te$sup 121$ AND Te$sup 123$, AND THE DECAY OF THE Te$sup 121$ ISOMERS TO Sb$sup 12$$sup 1$
Related Subjects
ALPHA DECAY
ANTIMONY 121
ANTIMONY 123
BEAMS
CONFIGURATION MIXING
DECAY
E2-TRANSITIONS
ELECTRON SPECTROSCOPY
FISSION
GAMMA RADIATION
GAMMA SPECTROSCOPY
HALF-LIFE
HIGH SPIN STATES
INCOMPLETE FUSION REACTIONS
ISOMERS
LITHIUM 7 BEAMS
MIXING
MULTI-NUCLEON TRANSFER REACTIONS
NEUTRON EMISSION
NEUTRONS
NUCLEAR REACTIONS
PROTONS
ROTATIONAL STATES
SPIN
TIN 120 TARGET
TIN 122 TARGET
XENON 136 BEAMS