Structure of ^126,128Xe studied by Coulomb excitation

The electromagnetic characteristics and structure of ^126,128Xe were studied by sub-barrier Coulomb excitation measurements performed at NSCL, MSU. Scattered nuclei and de-excitation gamma-rays were detected using the JANUS setup. Transition and diagonal matrix elements were determined from the experimental data using the GOSIA code. Experimental transition probabilities and quadrupole moments were compared to large-scale PMMU shell model calculations and phenomenological asymmetric rotor predictions. Quadrupole shape parameters were determined in a model-independent way. The results point out deviations from the O(6)-like structure in the ground state bands of both nuclei. The experimental data suggest near-zero quadrupole moment of the 2⁺₂ states, different from the higher-magnitude quadrupole moments of the 2⁺₁ states in ^126,128Xe.