Second minimum lifetime measurements in 133Nd and 137Nd.

Abstract

The quadrupole moments (${\mathit{Q}}_{0}$) of the highly deformed, second minimum bands in $^{133}\mathrm{Nd}$ and $^{137}\mathrm{Nd}$ have been extracted from mean lifetime measurements using the Doppler shift attenuation method. The reactions $^{105}\mathrm{Pd}$${(}^{32}$S,2p2n${)}^{133}$Nd at 152 MeV and $^{104}\mathrm{Ru}$${(}^{36}$S,3n${)}^{137}$Nd at 145 MeV were used. A standard centroid shift analysis was carried out in both cases, which gave values of ${\mathit{Q}}_{0}$=(6.0\ifmmode\pm\else\textpm\fi{}0.7)e b and (4.0\ifmmode\pm\else\textpm\fi{}0.5)e b for $^{133}\mathrm{Nd}$ and $^{137}\mathrm{Nd}$, respectively, corresponding to axial prolate deformations of ${\mathrm{\ensuremath{\beta}}}_{2}$\ensuremath{\simeq}0.33 and \ensuremath{\simeq}0.22. A line-shape analysis was also carried out for $^{133}\mathrm{Nd}$ to check against the possible effect of sidefeeding. The result was ${\mathit{Q}}_{0}$=(6.7+0.7)e b, with sightly slower sidefeeding times corresponding to ${\mathit{Q}}_{\mathrm{sf}}$\ifmmode\bar\else\textasciimacron\fi{}\ensuremath{\simeq}5.3e b. The results are in good agreement with the predictions of total Routhian surface calculations, and are discussed in the context of other highly deformed bands in the A=130--140 mass region.