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Title: Spectroscopy of the N=Z-2 nucleus {sup 46}Cr and mirror energy differences

Abstract

Excited states in {sup 46}Cr were sought using the {sup 12}C({sup 36}Ar,2n) reaction. Gamma rays were detected with the Gammasphere array, and the Z value of the reaction products was determined with an ionization chamber located at the focal plane of the Fragment Mass Analyzer. In addition to the ground-state band observed up to I{sup {pi}}=10{sup +} (tentatively 12{sup +}), five states are proposed to belong to the 3{sup -} band. The mirror energy differences with the analog states in {sup 46}Ti present a pronounced staggering effect between the odd and even spin members that is reproduced well by shell-model calculations incorporating the different Coulomb contributions, monopole, multipole, and single-particle effects together with an isospin-nonconserving interaction that accounts for the so-called J=2 anomaly. Dramatically different E1 decay patterns for members of the 3{sup -} band between the {sup 46}Cr and {sup 46}Ti mirrors are also observed.

Authors:
 [1];  [2];  [3];  [4]; ;  [5]; ; ;  [6]; ; ; ;  [7];  [8]
  1. Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1 (Canada)
  2. (United States)
  3. Dipartimento di Fisica and INFN, Padova (Italy)
  4. Department of Physics, Eskisehir Osmangazi University, Meselik, Eskisehir, TR-26480 (Turkey)
  5. Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada)
  6. Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)
  7. Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
  8. CLRC Daresbury Laboratory, Daresbury, Warrington, WA4 4AD (United Kingdom)
Publication Date:
OSTI Identifier:
20990946
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 1; Other Information: DOI: 10.1103/PhysRevC.75.014307; (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; ARGON 36; CARBON 12; CHROMIUM 46; ENERGY-LEVEL TRANSITIONS; EXCITED STATES; GAMMA RADIATION; GROUND STATES; HEAVY ION REACTIONS; IONIZATION CHAMBERS; ISOBARIC ANALOGS; ISOSPIN; MASS NUMBER; MIRRORS; SHELL MODELS; SPECTROSCOPY; SPIN; TITANIUM 46

Citation Formats

Garrett, P. E., Lawrence Livermore National Laboratory, Livermore, California 94551, Lenzi, S. M., Algin, E., Appelbe, D., Cameron, J. A., Bauer, R. W., Becker, J. A., Bernstein, L. A., Carpenter, M. P., Janssens, R. V. F., Lister, C. J., Seweryniak, D., and Warner, D. D. Spectroscopy of the N=Z-2 nucleus {sup 46}Cr and mirror energy differences. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.014307.
Garrett, P. E., Lawrence Livermore National Laboratory, Livermore, California 94551, Lenzi, S. M., Algin, E., Appelbe, D., Cameron, J. A., Bauer, R. W., Becker, J. A., Bernstein, L. A., Carpenter, M. P., Janssens, R. V. F., Lister, C. J., Seweryniak, D., & Warner, D. D. Spectroscopy of the N=Z-2 nucleus {sup 46}Cr and mirror energy differences. United States. doi:10.1103/PHYSREVC.75.014307.
Garrett, P. E., Lawrence Livermore National Laboratory, Livermore, California 94551, Lenzi, S. M., Algin, E., Appelbe, D., Cameron, J. A., Bauer, R. W., Becker, J. A., Bernstein, L. A., Carpenter, M. P., Janssens, R. V. F., Lister, C. J., Seweryniak, D., and Warner, D. D. Mon . "Spectroscopy of the N=Z-2 nucleus {sup 46}Cr and mirror energy differences". United States. doi:10.1103/PHYSREVC.75.014307.
@article{osti_20990946,
title = {Spectroscopy of the N=Z-2 nucleus {sup 46}Cr and mirror energy differences},
author = {Garrett, P. E. and Lawrence Livermore National Laboratory, Livermore, California 94551 and Lenzi, S. M. and Algin, E. and Appelbe, D. and Cameron, J. A. and Bauer, R. W. and Becker, J. A. and Bernstein, L. A. and Carpenter, M. P. and Janssens, R. V. F. and Lister, C. J. and Seweryniak, D. and Warner, D. D.},
abstractNote = {Excited states in {sup 46}Cr were sought using the {sup 12}C({sup 36}Ar,2n) reaction. Gamma rays were detected with the Gammasphere array, and the Z value of the reaction products was determined with an ionization chamber located at the focal plane of the Fragment Mass Analyzer. In addition to the ground-state band observed up to I{sup {pi}}=10{sup +} (tentatively 12{sup +}), five states are proposed to belong to the 3{sup -} band. The mirror energy differences with the analog states in {sup 46}Ti present a pronounced staggering effect between the odd and even spin members that is reproduced well by shell-model calculations incorporating the different Coulomb contributions, monopole, multipole, and single-particle effects together with an isospin-nonconserving interaction that accounts for the so-called J=2 anomaly. Dramatically different E1 decay patterns for members of the 3{sup -} band between the {sup 46}Cr and {sup 46}Ti mirrors are also observed.},
doi = {10.1103/PHYSREVC.75.014307},
journal = {Physical Review. C, Nuclear Physics},
number = 1,
volume = 75,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}
  • Excited states in {sup 46}Cr were sought using the {sup 12}C({sup 36}Ar,2n) reaction. Gamma rays were detected with the Gammasphere array, and the Z value of the reaction products was determined with an ionization chamber located at the focal plane of the Fragment Mass Analyzer. In addition to the ground-state band observed up to I{pi} = 10{sup +} (tentatively 12{sup +}), five states are proposed to belong to the 3{sup -} band. The mirror energy differences with the analog states in {sup 46}Ti present a pronounced staggering effect between the odd and even spin members that is reproduced well bymore » shell-model calculations incorporating the different Coulomb contributions, monopole, multipole, and single-particle effects together with an isospin-nonconserving interaction that accounts for the so-called J=2 anomaly. Dramatically different E1 decay patterns for members of the 3{sup -} band between the {sup 46}Cr and {sup 46}Ti mirrors are also observed.« less
  • The Gamow-Teller (GT) transition strengths in fp-shell nuclei are important parameters in presupernova models. A high-energy-resolution ({sup 3}He,t) experiment was performed on the T{sub z}=1 nucleus {sup 46}Ti at 0 deg. and at an intermediate incident energy of 140 MeV/nucleon for the study of precise GT transition strengths to the final T{sub z}=0 nucleus {sup 46}V. With an energy resolution of 33 keV, individual GT transitions were observed and GT strengths were derived for them up to the excitation energy of 4.5 MeV. The GT strengths were compared with shell-model calculations using various effective interactions. In this low-lying region, mostmore » GT states have isospin T=0. A few GT states with isospin T=1 were identified from the existence of the corresponding (analog) M1 states in {sup 46}Ti. By comparing the GT strength with the corresponding (analogous) M1 transition strength studied in {sup 46}Ti(e,e{sup '}) or ({gamma},{gamma}{sup '}) measurements, a large constructive interference of orbital and spin terms was suggested for one of these M1 transitions.« less
  • The complexes (Cr/sup III/(L)(O-O))/sup n/ (L = nitrilotriacetate (nta), N,N-..beta..-alaninediacetate (..beta..-alada); O-O = malonate (mal), oxalate (ox), acetylacetonate (acac), 2H/sub 2/O) have been synthesized, chromatographically purified, and characterized by deuteron NMR, infrared and electronic absorption spectroscopy. The two possible isomers, symmetrical (sym) and unsymmetrical (unsym), for (Cr(..beta..-alada)(acac))/sup -/ and (Cr(..beta..-alada)(mal))/sup 2 -/ were isolated, but only the unsym isomer for (Cr(..beta..-alada)(ox))/sup 2 -/ was found. The starting materials for the synthesis of these complexes, (Cr(nta)(OH))/sub 2//sup 2 -/ and unsym-(Cr(..beta..-alada)(H/sub 2/O)/sub 2/), were also characterized. Both species were shown to be in equilibrium with the corresponding monomer and dimer, respectively.more » The chemistry of the various species investigated differs, to some extent, from what has been previously reported. The recent availability of a readily applicable NMR technique for the study of Cr(III) chemistry (/sup 2/H NMR) has greatly facilitated these studies.« less