Different deformations for the two bands built above the (π${\mathit{h}}_{11/2}$${)}^2$ ${10}^{+}$ and the (ν${\mathit{h}}_{11/2}$${)}^{\mathrm{-}2}$ ${10}^{+}$ states in ${}_{}{}^{140}{}_{}{}^{}\mathrm{Sm}$ have been determined from lifetime measurements using the reaction ${}_{}{}^{106}{}_{}{}^{}\mathrm{Pd}$${(}^{37}$Cl,p2n${)}^{140}$Sm at 143 MeV. The β values derived for the N=78 and N=80 core nuclei, coexisting in ${}_{}{}^{140}{}_{}{}^{}\mathrm{Sm}$, complete the systematics of nuclear deformation from N=72 to 80.

• Received 17 April 1991

DOI:https://doi.org/10.1103/PhysRevC.44.891