Yrast Excitations around Doubly Magic<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow/><mml:mrow><mml:mn>132</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi>Sn</mml:mi></mml:math>from Fission Product<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>γ</mml:mi></mml:math>-Ray Studies
Annotatsiya
Prompt $\ensuremath{\gamma}$-ray cascades in neutron-rich nuclei around doubly magic ${}^{132}\mathrm{Sn}$ have been studied at Eurogam II using a ${}^{248}\mathrm{Cm}$ fission source. Yrast states to above 5.5 MeV in the two- and three-proton $N\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}82$ isotones ${}^{134}\mathrm{Te}$ and ${}^{135}\mathrm{I}$ are reported. They are interpreted in terms of valence proton and particle-hole core excitations with the help of shell model calculations employing empirical nucleon-nucleon interactions from both ${}^{132}\mathrm{Sn}$ and ${}^{208}\mathrm{Pb}$ regions. A serious inconsistency in the accepted masses of $N\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}82$ isotones near ${}^{132}\mathrm{Sn}$ is discovered but not resolved.