Coulomb excitation of Ru102 with C12 and O16

Abstract

The Coulomb excitation of $^{102}\mathrm{Ru}$ was performed with beams of $^{12}\mathrm{C}$ and $^{16}\mathrm{O}$ ions. The beam particles scattered at forward angles were momentum analyzed with a magnetic spectrograph. The resolution achieved enabled the populations of the ${2}_{1}^{+}$ state, the unresolved ${2}_{2}^{+}/{4}_{1}^{+}$, and ${2}_{4}^{+}/{3}_{1}^{\ensuremath{-}}$, doublets of states, and the ${3}_{2}^{\ensuremath{-}}$ state to be determined as a function of the scattering angle. These populations are compared with gosia calculations, yielding $B(E2;{2}_{1}^{+}\ensuremath{\rightarrow}{0}_{1}^{+})=41.5\ifmmode\pm\else\textpm\fi{}2.3$ W.u., $B(E2;{2}_{2}^{+}\ensuremath{\rightarrow}{0}_{1}^{+})=1.75\ifmmode\pm\else\textpm\fi{}0.11$ W.u., $B(E3;{3}_{1}^{\ensuremath{-}}\ensuremath{\rightarrow}{0}_{1}^{+})=31.5\ifmmode\pm\else\textpm\fi{}3.5$ W.u., and $B(E3;{3}_{2}^{\ensuremath{-}}\ensuremath{\rightarrow}{0}_{1}^{+})=6.8\ifmmode\pm\else\textpm\fi{}0.5$ W.u. The $B(E3;{3}_{1}^{\ensuremath{-}}\ensuremath{\rightarrow}{0}_{1}^{+})$ value is significantly larger than previously measured. The weakly populated ${2}_{3}^{+}$ state, presumed to be a member of the band built on the ${0}_{2}^{+}$ state, was observed clearly for a single angle only, and a fit to its population results in $B(E2;{2}_{3}^{+}\ensuremath{\rightarrow}{0}_{1}^{+})=0.053\ifmmode\pm\else\textpm\fi{}0.011$ W.u. Using the known $\ensuremath{\gamma}$-ray branching ratios for the ${2}_{3}^{+}$ level, the $B(E2;{2}_{3}^{+}\ensuremath{\rightarrow}{0}_{2}^{+})$ value is calculated to be $18\ifmmode\pm\else\textpm\fi{}4$ W.u., substantially less than the $B(E2;{2}_{1}^{+}\ensuremath{\rightarrow}{0}_{1}^{+})$. This suggests that the deformation of the ${0}_{2}^{+}$ state is lower than that of the ${0}_{1}^{+}$ state. The results are compared with beyond-mean-field calculations with the Gogny-D1S interaction using the symmetry-conserving configuration-mixing method.