High-spin structures in theXe129nucleus

Abstract

High-spin states in the Xe-129 nucleus are studied with the reaction Sn-124(Be-9,4n) at a beam energy of 36 MeV. The level scheme is extended significantly. For the positive-parity band, the alpha = +1/2 and the alpha = -1/2 signature components are combined to form a complete band structure based on the 3/2(+) state with spin and parity up to 21/2(+). For the negative-parity band based on the 11/2(-) state, the alpha = +1/2 signature component is newly established and both the alpha = +1/2 and the alpha = -1/2 signature components also form a complete band structure up to the 35/2(-) state. The positive-and negative-parity bands are proposed to originate from nu d(3/2) 3/2(+)[402] and nu h(11/2)11/2(-)[505] Nilsson configurations, respectively. A backbending is observed in the negative-parity band, which originates from the alignments of two h(11/2) protons according to crank shell model calculations. Based on the total Routhian surface and quasiparticle triaxial rotor model calculations, the negative-parity band is interpreted as a triaxially deformed shape with gamma approximate to -30 degrees, while the positive-parity band is associated with. softness, in accordance with previous studies. In the high-spin states, three decoupled bands and one oblate band with gamma approximate to -60 degrees are newly identified. The systematics and other characteristics of these bands are discussed.