OBLATE L = 1 BANDS IN 194,196-201PB AND 193HG

Reports of recent experiments have included observations of regular an d irregular bands in neutron deficient Pb isotopes with A = 194, 196-2 01. The bands are populated strongly in (HI, xn) reactions. The shared characteristics of the bands include: 1) bandhead energies of a few M eV; 2) high bandhead spin; 3) large alignments; 4) small dynamic momen ts of inertia, and 5) strong L = 1 transitions and weaker L = 2 crosso ver transitions, with B(Ml)/B(E2) almost-equal-to 20 mu2/e2 b2. Lifeti mes of band members in the Pb-198 regular band are B(M1) almost-equal- to 1 W.u. and B(E2) almost-equal-to 12 W.u. (with large errors). These observations are consistent with an interpretation of the regular str uctures as collective oblate bands with both proton and neutron excita tions involved; the closed proton shell at Z = 82 is broken, and coupl ed to nu(i13/2)-n excitations. The irregular structures may correspond to triaxial shapes, with similar orbits involved. A similar structure has been also found in 193Hg.