A set of $B\left(E2\right)$ values for the low-lying excited states in the radioactive isotope ${}^{109}$Sn were deduced from a Coulomb excitation experiment. The 2.87-MeV/$u$ radioactive beam was produced at the REX-ISOLDE facility at CERN and was incident on a secondary ${}^{58}$Ni target. The $B\left(E2\right)$ values were determined using the known $2^{+}\to 0^{+}$ reduced transition probability in ${}^{58}$Ni as normalization with the semiclassical Coulomb excitation code gosia2. The transition probabilities are compared to shell-model calculations based on a realistic nucleon-nucleon interaction and the predictions of a simple core-excitation model. This measurement represents the first determination of multiple $B\left(E2\right)$ values in a light Sn nucleus using the Coulomb excitation technique with low-energy radioactive beams. The results provide constraints for the single-neutron states relative to ${}^{100}$Sn and also indicate the importance of both single-neutron and collective excitations in the light Sn isotopes.

• Received 13 July 2012

DOI:https://doi.org/10.1103/PhysRevC.86.031302