Location and description of some low-lying high-spin states in 155Gd

The reaction 154Sm(α, 3n)155Gd has been used to populate states in 155Gd. Cascade and crossover transitions are observed within a strongly perturbed rotational band which is populated up to spin 252. A calculation in which the Nilsson-model Hamiltonian is extended to include Coriolis and ΔN = 2 couplings can successfully account for the experimental energies, intensities and angular distributions in the positive-parity band. This calculation suggests that the band is a rather complete mixture of the 12+ [660], 32+ [651], 52+ [642], 72+ [633], 12+ [400] and 32+[402] Nilsson orbitals. Rotational bands built on the intrinsic states 32−[521] and 112−[505] are also observed. The moment of inertia for the 112− [505] band is discussed.