First Measurement of Collectivity of Coexisting Shapes based on Type II   Shell Evolution: The Case of $^{96}$Zr
  Background: Type II shell evolution has recently been identified as a microscopic cause for nuclear shape coexistence. Purpose: Establish a low-lying rotational band in 96-Zr. Methods: High-resolution inelastic electron scattering and a relative analysis of transition strengths are used. Results: The B(E2; 0_1^+ -> 2_2^+) value is measured and electromagnetic decay strengths of the secdond 2^+ state are deduced. Conclusions: Shape coexistence is established for 96-Zr. Type II shell evolution provides a systematic and quantitative mechanism to understand deformation at low excitation energies. 
C. Kremer, S. Aslanidou, S. Bassauer, M. Hilcker, A. Krugmann, P. von   Neumann-Cosel, T. Otsuka, N. Pietralla, V. Yu. Ponom...
nucl-ex nucl-th