Weakly deformed oblate structures in Os

Podolyk, Zs.*; Steer, S. J.*; Pietri, S.*; Xu, F. R.*; Liu, H. J.*; Regan, P. H.*; Rudolph, D.*; Garnsworthy, A. B.*; Hoischen, R.*; Grska, M.*; Gerl, J.*; Wollersheim, H. J.*; Kurtukian-Nieto, T.*; Benzoni, G.*; Shizuma, Toshiyuki; Becker, F.*; Bednarczyk, P.*; Cceres, L.*; Doornenbal, P.*; Geissel, H.*; Grbosz, J.*; Kelic, A.*; Kojouharov, I.*; Kurz, N.*; Montes, F.*; Prokopowicz, W.*; Saito, Takehiko*; Schaffner, H.*; Tashenov, S.*; Heinz, S.*; Pftzner, M.*; Jungclaus, A.*; Balabanski, D. L.*; Brandau, C.*; Bruce, A. M.*; Catford, W. N.*; Cullen, I. J.*; Dombrdi, Zs.*; Estevez, E.*; Gelletly, W.*; Ilie, G.*; Jolie, J.*; Jones, G. A.*; Kmiecik, M.*; Kondev, F. G.*; Krcken, R.*; Lalkovski, S.*; Liu, Z.*; Maj, A.*; Myalski, S.*; Schwertel, S.*; Walker, P. M.*; Werner-Malento, E.*; Wieland, O.*

rays de-exciting isomeric states in the neutron-rich nucleus Os have been observed following relativistic projectile fragmentation of a 1 GeV per nucleon Pb beam. The ground-state band has properties compatible with oblate deformation. The evolution of the structure of Os isotopes characterized by sudden prolate-oblate shape change is discussed and contrasted with the smooth change known in the Pt chain.