0000000000602904
AUTHOR
S. W. Yates
Two-phonon octupole excitation inGd146
Based on experimental evidence from the $^{144}\mathrm{Sm}$($\ensuremath{\alpha},2n$) reaction, the $3484.7$-keV ${6}^{+}$ state in $^{146}\mathrm{Gd}$ is identified as the highest-spin member of the ${3}^{\ensuremath{-}}\ensuremath{\bigotimes}{3}^{\ensuremath{-}}$ two-phonon octupole quartet. A previously unknown $\ensuremath{\gamma}$ line of $1905.8$ keV and $E3$ character feeding the ${3}^{\ensuremath{-}}$ octupole state has been observed. These results represent the first observation of a ${6}^{+}\ensuremath{\rightarrow}{3}^{\ensuremath{-}}\ensuremath{\rightarrow}{0}^{+}$ cascade of two $E3$ transitions in an even-even nucleus and provide strong support for the interpretation of the ${6…
Conversion-electron study of 0+excitations in208Pb
The 208Pb(p,p'e−) reaction has been studied at a proton energy of 17.3 MeV. Singles data show E0 transitions from the 0+2 and 0+3 states at 4868 and 5241 keV, respectively, to the ground state. Proton–electron gated spectra indicate that few electrons from the 0+2 state are in coincidence with backscattered protons, while those from the 0+3 state are somewhat more abundant. From the singles spectra, an upper limit for the E3(0+3 → 3−1)/E0(0+3 → 0+1) branching ratio of less than four has been measured. This observation is in agreement with previous predictions for a two-phonon octupole excitation.
Two-Phonon Octupole Excitation in 146Gd
The excited states in 146Gd have been re‐investigated with the 144Sm(α,2n) reaction using a modern Ge γ‐ray array including a polarimeter. Amongst the non‐yrast states populated in this reaction we have identified the aligned 6+ member of the two‐phonon octupole quartet from the observation of the E3 branching to the one phonon 3− state. Our results represent the first observation of a 6+→3−→0+ E3 cascade in an even‐even nucleus.
Single-Particle Excitations and Collective Vibrational Modes in 96Zr
New results from (n,n’γ) and (p,p’γ) reactions, as well as from β- decay confirm the double subshell closure in 96Zr and provide a detailed level scheme for this nucleus. The 1750 keV first 2+ state is described as a neutron particle-hole excitation, while the positive-parity band built on the 1582 keV excited 0+ state is characterised by quadrupole vibrational collectivity at low spins. Candidates for two-phonon octupole, quadrupole-octupole and higher multipole states are suggested on the basis of fast El and E2 decays to the 3- octupole state. The recently observed large octupole strength, its inverse relationship with the filling of the νlh11/2 orbital, and the onset of quadrupole defor…