Nuclear shapes of the transitional nuclei 186, 188, 190, 192Os

Abstract

Excitation functions at θ lab = 130° have been measured for inelastic scattering of 13–24 MeV alpha particles from 186,188,190,192Os. Data have been obtained for 0 +, 2 +, 4 +, 2 +' states in 186,188,192Os and for 0 +, 2 + states in 190Os. Charge and mass quadrupole deformations, β 2 c and β 2 N, were deduced from coupled-channels analysis of the 2 + data. No simple model could provide good fits to the 4 + data over the entire energy range but the very deep interference minima observed establish the charge and mass hexadecapole moments, β 4 c and β 4 N, to be negative. The energies of the interference minima for the 4 + states could be reproduced by coupled-channels calculations only if large differences in β 4 c and β 4 N were allowed. Data for the ( J, K) π = (2, 2) + states are inconsistent with an asymmetric rotational model.