In-beam γ-ray spectroscopy of the odd-odd nucleus ¹⁸⁶Re

Excited states in ¹⁸⁶Re were investigated in two separate experiments using ¹⁸⁶W(d,2n) reactions at beam energies of 12.5 MeV and 14.5 MeV. Two- and three-fold γ-ray coincidence data were collected using the CAESAR and CAGRA spectrometers, respectively, each composed of Compton-suppressed HPGe detectors. Analysis of the data revealed rotational bands built on several two quasiparticle intrinsic states, including a long-lived K^π=(8⁺) isomer. The excitation energies of the observed intrinsic states were compared with results from multi-quasiparticle blocking calculations, based on the Lipkin-Nogami pairing approach, that included contributions from the residual proton-neutron interactions.