The N=90 transitional nuclei sup 1 sup 5 sup 0 Nd and sup 1 sup 5 sup 2 Sm revisited

The purpose of this paper is to show that recent data on the ground-state band and excited states based on the 0 sub 2 sup + level in sup 1 sup 5 Nd and sup 1 sup 5 sup 2 Sm, especially the measured B(E2) values, can be well described by including a DELTA K = 0 coupling between rotational bands. This is contrary to recent statements in the literature. The experimental data are compared with models which have supported the widely differing interpretations of these transitional nuclei. These interpretations include describing excited states as rotational excitations of single-phonon states, the multiphonon ''phase coexistence'' picture, and the X(5) critical-point description.