Shape coexistence and evolution in neutron-deficient krypton isotopes

Abstract：

Total Routhian Surface (TRS) calculations have been performed to investigate shape coexistence and evolution in neutron-deficient krypton isotopes ^72,74,76Kr. The ground-state shape is found to change from oblate in ⁷²Kr to prolate in ^74,76Kr, in agreement with experimental data. Quadrupole deformations of the ground states and coexisting 0₂⁺ states as well as excitation energies of the latter are also well reproduced. While the general agreement between calculated moments of inertia and those deduced from observed spectra confirms the prolate nature of the low-lying yrast states of all three isotopes (except the ground state of ⁷²Kr), the deviation at low spins suggests significant shape mixing. The role of triaxiality in describing shape coexistence and evolution in these nuclei is finally discussed.