Quasiparticle alignments andα-decay fine structure of175Pt

Abstract

Excited states and decay properties of 175 Pt have been investigated using the 92 Mo(86 Sr,2pn) fusion-evaporation reaction. The JUROGAM I γ-ray spectrometer and the GREAT spectrometer were used in conjunction with the gas-filled recoil separator RITU for the measurement of the radiation at the target and focal plane positions, respectively. Two new band structures, assigned to be based on the I π = (7 /2 −) ground state in 175 Pt, have been established and the known yrast band has been extended up to I π = (49 /2 +). Rotational properties of the excited states in 175 Pt have been investigated within the cranked shell-model formalism. The low-frequency changes in the alignments of the positive-and negative-parity bands are interpreted as a sign of proton-pair excitations in the rotating core. Furthermore, the α-decay measurements reveal a candidate for a fourth α-decay branch in 175 Pt, feeding a non-yrast state in 171 Os.