The Kr isotopes with A=72 to 84 are investigated within the interacting boson model (IBM-2) using two different approaches. In the first investigation the single-particle energies of the neutron and proton bosons are assumed equal, ε=${\mathrm{\epsilon }}_{\nu }$=${\mathrm{\epsilon }}_{\mathrm{\pi }}$, whereas the second investigation is based on their being different (${\mathrm{\epsilon }}_{\nu }$≠${\mathrm{\epsilon }}_{\mathrm{\pi }}$). The results of these calculations are compared with the experimental data and previous theoretical investigations. We also attempt to determine the shape transition in these nuclei.

• Received 26 July 1994

DOI:https://doi.org/10.1103/PhysRevC.51.573