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Title: Spin dependence of K mixing, strong configuration mixing, and electromagnetic properties of {sup 178}Hf

Abstract

The combined data of two Coulomb excitation experiments has verified the purely electromagnetic population of the K{sup {pi}}=4{sup +},6{sup +},8{sup -}, and 16{sup +} rotational bands in {sup 178}Hf via 2{<=}{nu}{<=}14 K-forbidden transitions, quantifying the breakdown of the K-selection rule with increasing spin in the low-K bands. The {gamma}-, 4{sup +}, and 6{sup +} bands were extended, and four new states in a rotational band were tentatively assigned to a previously known K{sup {pi}}=0{sup +} band. The quasiparticle structure of the 6{sup +} (t{sub (1/2)}=77 ns) and 8{sup -} (t{sub (1/2)}=4 s) isomer bands were evaluated, showing that the gyromagnetic ratios of the 6{sup +} isomer band are consistent with a pure {pi}(7/2){sup +}[404],{pi}(5/2){sup +}[402] structure. The 8{sup -} isomer band at 1147 keV and the second 8{sup -} band at 1479 keV, thought to be predominantly {nu}(7/2){sup -}[514],{nu}(9/2){sup +}[624] and {pi}(9/2){sup -}[514],{pi}(7/2){sup +}[404], respectively, are mixed to a degree approaching the strong-mixing limit. Based on measured <K{sup {pi}}=16{sup +} parallel E 2 parallel K{sup {pi}}=0{sup +}> matrix elements, it was shown that heavy-ion bombardment could depopulate the 16{sup +} isomer at the {approx}1% level, although no states were found that would mediate photodeexcitation of the isomer via low-energy x-raymore » absorption.« less

Authors:
; ; ; ;  [1];  [1];  [2]; ; ; ; ; ; ;  [3];  [4]; ; ;  [5]; ; more »;  [6] « less
  1. Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States)
  2. (United States)
  3. Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520 (United States)
  4. Physics Department, University of Richmond, Richmond, Virginia 23173 (United States)
  5. GSI, Gesellschaft fuer Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt (Germany)
  6. Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States) (and others)
Publication Date:
OSTI Identifier:
20995121
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevC.75.034308; (c) 2007 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; ABSORPTION; CONFIGURATION MIXING; COULOMB EXCITATION; FORBIDDEN TRANSITIONS; GYROMAGNETIC RATIO; HAFNIUM 178; HEAVY IONS; ISOMERS; KEV RANGE; MATRIX ELEMENTS; MIXING; ROTATIONAL STATES; SELECTION RULES; SPIN; X RADIATION

Citation Formats

Hayes, A. B., Cline, D., Hua, H., Simon, M. W., Teng, R., Wu, C. Y., Lawrence Livermore National Laboratory, Livermore, California 94550, Ai, H., Amro, H., Casten, R. F., Hecht, A. A., Heinz, A., Hughes, R., Meyer, D. A., Beausang, C., Gerl, J., Schlegel, Ch., Wollersheim, H. J., Janssens, R. V. F., Lister, C. J., and Moore, E. F. Spin dependence of K mixing, strong configuration mixing, and electromagnetic properties of {sup 178}Hf. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.034308.
Hayes, A. B., Cline, D., Hua, H., Simon, M. W., Teng, R., Wu, C. Y., Lawrence Livermore National Laboratory, Livermore, California 94550, Ai, H., Amro, H., Casten, R. F., Hecht, A. A., Heinz, A., Hughes, R., Meyer, D. A., Beausang, C., Gerl, J., Schlegel, Ch., Wollersheim, H. J., Janssens, R. V. F., Lister, C. J., & Moore, E. F. Spin dependence of K mixing, strong configuration mixing, and electromagnetic properties of {sup 178}Hf. United States. doi:10.1103/PHYSREVC.75.034308.
Hayes, A. B., Cline, D., Hua, H., Simon, M. W., Teng, R., Wu, C. Y., Lawrence Livermore National Laboratory, Livermore, California 94550, Ai, H., Amro, H., Casten, R. F., Hecht, A. A., Heinz, A., Hughes, R., Meyer, D. A., Beausang, C., Gerl, J., Schlegel, Ch., Wollersheim, H. J., Janssens, R. V. F., Lister, C. J., and Moore, E. F. Thu . "Spin dependence of K mixing, strong configuration mixing, and electromagnetic properties of {sup 178}Hf". United States. doi:10.1103/PHYSREVC.75.034308.
@article{osti_20995121,
title = {Spin dependence of K mixing, strong configuration mixing, and electromagnetic properties of {sup 178}Hf},
author = {Hayes, A. B. and Cline, D. and Hua, H. and Simon, M. W. and Teng, R. and Wu, C. Y. and Lawrence Livermore National Laboratory, Livermore, California 94550 and Ai, H. and Amro, H. and Casten, R. F. and Hecht, A. A. and Heinz, A. and Hughes, R. and Meyer, D. A. and Beausang, C. and Gerl, J. and Schlegel, Ch. and Wollersheim, H. J. and Janssens, R. V. F. and Lister, C. J. and Moore, E. F.},
abstractNote = {The combined data of two Coulomb excitation experiments has verified the purely electromagnetic population of the K{sup {pi}}=4{sup +},6{sup +},8{sup -}, and 16{sup +} rotational bands in {sup 178}Hf via 2{<=}{nu}{<=}14 K-forbidden transitions, quantifying the breakdown of the K-selection rule with increasing spin in the low-K bands. The {gamma}-, 4{sup +}, and 6{sup +} bands were extended, and four new states in a rotational band were tentatively assigned to a previously known K{sup {pi}}=0{sup +} band. The quasiparticle structure of the 6{sup +} (t{sub (1/2)}=77 ns) and 8{sup -} (t{sub (1/2)}=4 s) isomer bands were evaluated, showing that the gyromagnetic ratios of the 6{sup +} isomer band are consistent with a pure {pi}(7/2){sup +}[404],{pi}(5/2){sup +}[402] structure. The 8{sup -} isomer band at 1147 keV and the second 8{sup -} band at 1479 keV, thought to be predominantly {nu}(7/2){sup -}[514],{nu}(9/2){sup +}[624] and {pi}(9/2){sup -}[514],{pi}(7/2){sup +}[404], respectively, are mixed to a degree approaching the strong-mixing limit. Based on measured <K{sup {pi}}=16{sup +} parallel E 2 parallel K{sup {pi}}=0{sup +}> matrix elements, it was shown that heavy-ion bombardment could depopulate the 16{sup +} isomer at the {approx}1% level, although no states were found that would mediate photodeexcitation of the isomer via low-energy x-ray absorption.},
doi = {10.1103/PHYSREVC.75.034308},
journal = {Physical Review. C, Nuclear Physics},
number = 3,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}