Abstract

The vibrational and rotational characteristics of the ground bands of even-even nuclei with 150 < A < 166 (2 < i?4< 3) are studied. The spectra of these nuclei (with band crossing angular momentum 7C > 12) are analyzed with a cubic polynomial in I. The considered nuclei (150Sm, Gd, 154~156Dy, 156E r,158-16°-162Yb and 162,164, 166Hf) lie in the central region between theZ = 50 and Z = 82 major shell closures and span the spherical to the well deformed region. The gradual shape * transition from a soft spherical vibrator to a deformed rotor from 150Sm to 166Hf is thus made explicitly apparent from the g-band spectrum analysis in terms of the vibrational, rotational and softness coefficients. The transition at N — 88-90 for the vibrational-rotational ratios and for the kinematic moments of inertia are reproduced.