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Title: Near-yrast structure of the {sup 109}Mo nucleus

Abstract

Excited states in {sup 109}Mo, populated in the spontaneous fission of {sup 248}Cm, were studied using the EUROGAM2 array. Octupole deformation reported previously in {sup 109}Mo was not confirmed. Spin and parity of the ground state were changed. A new band found in this work suggests the 5/2{sup +}[402] neutron configuration for the ground state. In the 222.2 keV band, the 110.8 and 138.9 keV transitions are of M1 + E2 instead of E1 multipolarity, as reported previously. The 222.2 keV band is explained as the 7/2{sup -}[523] neutron configuration.

Authors:
; ; ;  [1]; ; ;  [2];  [3]
  1. Faculty of Physics, Warsaw University, ul. Hoza 69, PL-00-681 Warsaw (Poland)
  2. Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom)
  3. Argonne National Laboratory, Argonne, Illinois 60439 (United States)
Publication Date:
OSTI Identifier:
20771401
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 73; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevC.73.037302; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; CURIUM 248; E1-TRANSITIONS; E2-TRANSITIONS; EXCITED STATES; GROUND STATES; KEV RANGE; MOLYBDENUM 109; MULTIPOLARITY; NEUTRONS; NUCLEAR DEFORMATION; OCTUPOLES; PARITY; SPIN; SPONTANEOUS FISSION; YRAST STATES

Citation Formats

Urban, W., Droste, Ch., Rzaca-Urban, T., Zlomaniec, A., Durell, J.L., Smith, A. G., Varley, B. J., and Ahmad, I. Near-yrast structure of the {sup 109}Mo nucleus. United States: N. p., 2006. Web. doi:10.1103/PhysRevC.73.037302.
Urban, W., Droste, Ch., Rzaca-Urban, T., Zlomaniec, A., Durell, J.L., Smith, A. G., Varley, B. J., & Ahmad, I. Near-yrast structure of the {sup 109}Mo nucleus. United States. doi:10.1103/PhysRevC.73.037302.
Urban, W., Droste, Ch., Rzaca-Urban, T., Zlomaniec, A., Durell, J.L., Smith, A. G., Varley, B. J., and Ahmad, I. Wed . "Near-yrast structure of the {sup 109}Mo nucleus". United States. doi:10.1103/PhysRevC.73.037302.
@article{osti_20771401,
title = {Near-yrast structure of the {sup 109}Mo nucleus},
author = {Urban, W. and Droste, Ch. and Rzaca-Urban, T. and Zlomaniec, A. and Durell, J.L. and Smith, A. G. and Varley, B. J. and Ahmad, I.},
abstractNote = {Excited states in {sup 109}Mo, populated in the spontaneous fission of {sup 248}Cm, were studied using the EUROGAM2 array. Octupole deformation reported previously in {sup 109}Mo was not confirmed. Spin and parity of the ground state were changed. A new band found in this work suggests the 5/2{sup +}[402] neutron configuration for the ground state. In the 222.2 keV band, the 110.8 and 138.9 keV transitions are of M1 + E2 instead of E1 multipolarity, as reported previously. The 222.2 keV band is explained as the 7/2{sup -}[523] neutron configuration.},
doi = {10.1103/PhysRevC.73.037302},
journal = {Physical Review. C, Nuclear Physics},
number = 3,
volume = 73,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}
  • Excited levels in the {sup 109}Tc nucleus, populated in the spontaneous fission of {sup 248}Cm, have been studied using the EUROGAM2 array. In {sup 109}Tc we have found a new band corresponding to the {pi}5/2{sup -}[303] configuration and a three-quasiparticle band with I{sup {pi}}=(15/2{sup -}) band-head level at 1749.5 keV. The structure of the 1749.5-keV level probably involves the {l_brace}{pi}5/2{sup +}[422]{nu}(5/2{sup -}[532],5/2{sup +}[413]){r_brace}{sub 15/2}{sup -} prolate configuration. The quasiparticle-rotor model calculations performed in this work show that the odd-proton configurations observed in {sup 107}Tc and {sup 109}Tc are consistent with the scheme of proton excitations in a prolate triaxial potential.more » Significant differences between the degree of triaxiality observed for positive- and negative-parity excitations may be due to blocking of the triaxial shape by the odd proton populating negative-parity orbitals. The properties of the new 494.5-, 1440.7-, and 1748.8-keV levels found in {sup 109}Tc may indicate a change toward an oblate shape in this nucleus.« less
  • Excited states in {sup 107}Mo, populated in spontaneous fission of {sup 248}Cm, were studied by use of the eurogam2 multidetector array. Spins and parities of the ground state and the 66.0-, 152.1-, and 458.5-keV excited levels, reported previously, were changed based on conversion-coefficient and angular-correlation measurements. Octupole deformation reported previously in {sup 107}Mo is dismissed, and we explain the near-yrast structure of {sup 107}Mo in terms of rotational bands built on the 5/2{sup +}[413], 3/2{sup +}[411], and 7/2{sup -}[523] orbitals.
  • We have reinvestigated the structure of the {sup 107}Tc nucleus reported in other works. Excited states in {sup 107}Tc, populated in spontaneous fission of {sup 248}Cm, were studied by means of prompt-{gamma} spectroscopy, using the EUROGAM2 multidetector array. Parity assignments to the 45.6 and 65.6 keV levels were changed, based on conversion coefficient measurements. A new band found on top of the 45.6 keV level corresponds to the {pi}5/2{sup -}[303] configuration. The positive-parity, yrast band in {sup 107}Tc is built on top of the 65.6 keV level and corresponds to the {pi}5/2{sup +}[422] configuration. The configurations observed in {sup 107}Tcmore » agree well with the scheme of single-proton excitations calculated for this nucleus.« less
  • Excited states in {sup 149}La, populated in the spontaneous fission of {sup 248}Cm, were studied with the EUROGAM2 array. A new {delta}I=2 band found in {sup 149}La is interpreted as the {alpha}=-1/2 branch of the {pi}3/2{sup -}[402] configuration. The bandhead has spin 7/2{sup -} because the 3/2{sup -} and 5/2{sup -} levels are pushed up by the Coriolis interaction. The 7/2{sup -} level is located not higher than 30 keV above the ground state and may form a long-lived isomer if spin and parity of the g.s. is 3/2{sup +}.
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