Collective states and shape competition in 126 Te

High-spin states in Te-126 have been investigated by using in-beam gamma ray spectroscopy with the Sn-124(Li-7, 1p4n)Te-126 reaction at a beam energy of 48 MeV. The previously known level scheme has been enriched, and a new negative-parity sequence has been established. The yrast positive-parity band shows a shape change between triaxial shape and collective oblate shape as a function of spin. In particular, three competitive minima appear in the potential energy surface for the I-pi = 8(+) states, with one aligned state at gamma = 120 degrees and two triaxial states at gamma similar to 30 degrees and -45 degrees, respectively. The signature splitting behavior of the negative-parity band is discussed. The shape change with increasing angular momentum and the signature splitting can be interpreted well in terms of the Cranked Nilsson-Strutinsky-Bogoliubov and Cranked Nilsson-Strutinsky model calculations.