Blocking effect and odd-even differences in the moments of inertia of rare-earth nuclei

Abstract

A phenomenological analysis of the experimental odd-even differences in the moments of inertia, \ensuremath{\delta}J/J, of well-deformed rare-earth nuclei is reviewed, which reveals that there exist large fluctuations in \ensuremath{\delta}J/J with the blocked levels in odd-A nuclei. A calculation using the particle-number conserving treatment shows that the odd-even difference in the moments of inertia is a pure quantum mechanical interference effect and the experimental strong fluctuations in \ensuremath{\delta}J/J with the blocked level can be reproduced satisfactorily. The calculated value of \ensuremath{\delta}J/J depends sensitively on the energetic location and Coriolis response of the blocked level and the underlying physics is discussed. Particularly, \ensuremath{\delta}J/J is especially large if the blocked orbital is a high-j intruder orbital near the Fermi surface. In contrast, if the blocked orbital is of normal parity with low j and high \ensuremath{\Omega} (e.g., proton [404] 7/2, [402]5/2), \ensuremath{\delta}J/J almost vanishes.