Microscopic Structure of the Yrast Bands in Even Xe Isotopes
The interaction between collective states consisting mainly of the lowest-energy quadrupole phonons is considered along with that of noncollective states, including high-spin phonons in even Xe isotopes. Calculations are performed for yrast states with spins of up to $${{I}^{\pi }} = {{18}^{ + }}$$ in the boson approximation. Collective states are gradually substituted for noncollective ones in isotopes with $$A \leqslant 120$$, leading to a smooth change in values of $$B(E2)$$ as spin increases. In contrast, there is a sharp transition from the collective to the noncollective band in isotopes with $$A \geqslant 122$$: the bands intersect and the corresponding $$B(E2)$$ value falls substantially.