R. Suchannek

192Os(α, α′) reaction at Eα = 24 MeV and the IBA model

Abstract Angular distributions of 24 MeV alpha particles elastically and inelastically scattered from 192 Os have been measured for the angular range θ lab = 50°–140°. Data are reportedhere for 0 + , 2 + 1 , 2 + 2 , 4 + 1 , 4 + 2 and 4 + 3 states. Coupled-channels analysis of the data was performed using matrix elements predicted by the interacting boson model assuming 192 Os to be a perturbed O(6) nucleus. Fits to the data are excellent for the ground band (0 + , 2 + 1 , 4 + 1 ), fairly good for the quasi-gamma band (2 + 2 , 4 + 2 ), and poor for the K = 4 band (4 + 3 ).

Sensitivity of (α, α′) cross sections to excited-state quadrupole moments

Abstract Angular distributions for excitation of the 1.20 MeV second 2+ state in 180Hf by 21 and 24 MeV α-particles have been measured. Coupled-channels calculations show substantial sensitivity to the assumed quadrupole moment of this state. The data are best-fitted by calculations using the value of the quadrupole moment expected if the state is a simple λ-vibrational level.

182, 184, 186W(α, α') Reactions at Eα = 24 MeV

Abstract Angular distributions of 24 MeV α-particles elastically and inelastically scattered from 182, 184, 186 W have been measured for the angular range θ lab = 40°–140°. Coupled-channels analyses of the data for the ground-state rotational bands which assume a symmetric-rotor model lead to the conclusion that, for each nucleus, the β 2 and β 4 deformation parameters for the Coulomb and the nuclear potentials are quite different ; these differences are not accounted for by the geometrical scaling method of Hendrie but are, in most cases, accounted for by the multipole-moment method of Mackintosh. A rigid asymmetric-rotor model is found to provide a good description of the data for excitation of the second 2 + state in 186 W. A second-order rotational-vibrational model provides a good description of the excitation of the 3 − state in 184 W and suggests that transitions other than the direct excitation (0 + → 3 − ) play an important role in the description of the data; this interpretation, however, fails to clearly distinguish between K = 0 and K = 2 models for the 3 − state.