Semi-decoupled band and other high-spin band structures in 188Pt.

High-spin states in the 188Pt nucleus have been investigated employing the 174Yb(18O,4n)188Pt reaction. The level scheme has been significantly extended with the addition of several new γ rays. The Indian National Gamma Array (INGA) spectrometer consisting of eighteen clover Ge detectors facilitated angular correlation and linear polarization measurements for spin-parity assignment of levels. The Iπ=5- semi-decoupled band has been investigated in detail, and the long-standing ambiguity regarding the correct ordering of associated γ rays is now removed with the new observation of transitions linking the even-spin levels to the odd-spin ones. A weak, ΔI=2 sequence of γ rays with alignment and moment of inertia similar to the yrast, even-spin, rotation-aligned neutron i13/2 band has been newly observed. Cranking calculations suggest that this new odd-spin sequence arises from the excitation of a valence quasineutron to the next i13/2 level. [ABSTRACT FROM AUTHOR]