Moments of inertia of the even-even rare earth nuclei below and above N=82

A systematic disagreement has been found between the results of the deformed shell model calculations and the phenomenological Grodzins estimate for nuclear deformations in the even-even rare-earth nuclei. As a rule, the Grodzins formula overpredicts deformations for N>82 and gives too small values for N<82. The authors have shown that these discrepancies can be explained by the N and Z dependence of the pairing field. Assuming the calculated deformations and the microscopic pairing gaps the experimentally observed behaviour of the nuclear moments of inertia is reproduced.