Levels above the 19 / 2 − isomer in Cu 71 </mml:…
2009; American Institute of Physics; Volume: 79; Issue: 3 Linguagem: Inglês
10.1103/physrevc.79.034319
ISSN1538-4497
AutoresI. Ştefânescu, W. B. Walters, R. V. F. Janssens, N. Hoteling, R. Broda, M. P. Carpenter, B. Fornal, A. A. Hecht, W. Królas, T. Lauritsen, T. Pawłat, D. Seweryniak, J. R. Stone, X. Wang, A. Wöhr, J. Wrzesiński, S. Zhu,
Tópico(s)Atomic and Molecular Physics
ResumoTwo prompt $\ensuremath{\gamma}$ rays of energies 2020 and 554 keV were observed in coincidence with delayed transitions depopulating the ${19/2}^{\ensuremath{-}}$ isomer in the $Z=29$, $N=42$ $^{71}\mathrm{Cu}$ nucleus. The newly identified transitions are proposed to deexcite the 4776- and 5330-keV levels above the ${19/2}^{\ensuremath{-}}$ isomer. Based on the comparison with the low-lying positive-parity states observed in the $Z=42$, $N=50$ $^{92}\mathrm{Mo}$ nucleus, spin and parity ${23/2}^{\ensuremath{-}}$ are proposed for the 4776-keV level in $^{71}\mathrm{Cu}$. The high-energy, 2020-keV transition is interpreted as arising from the breaking of the $N=40$ neutron core. Shell-model calculations with a $^{56}\mathrm{Ni}$ core reproduce the $(23/{2}^{\ensuremath{-}})\ensuremath{\rightarrow}(19/{2}^{\ensuremath{-}})$ gap well, suggesting that the ${23/2}^{\ensuremath{-}}$ state is dominated by $\ensuremath{\pi}{p}_{3/2}\ensuremath{\nu}((\mathit{fp}){}^{10}({g}_{9/2}){}^{4})$ configurations. The present result constitutes further evidence supporting the view that the $N=40$ subshell closure persists in $^{71}\mathrm{Cu}$, herewith challenging recent suggestions that the coupling of two or more proton or neutron quasiparticles induces a large polarization of the $^{68}\mathrm{Ni}$ core.
Referência(s)