Oblate bands in A approximately 200 bismuth nuclei

Abstract

The nuclei 198-200Bi were populated via the 186W(19F,xn)198-200Bi reaction at beam energies of 115 MeV and 105 MeV. Another experiment, aimed at investigating the high-spin-level structure of 203,204Bi, used the 198Pt(11B,xn) reaction at a beam energy of 74 MeV. Five new Delta I=1 rotational structures, consisting of stretched magnetic dipole transitions, have been observed. One of these bands is assigned to 198Bi, one to 199Bi, two to 200Bi, and one to 203Bi. The behaviour of the dynamic moments of inertia of these oblate bands is compared with other bands in neighbouring Pb and Bi nuclei.