Proton emission, gamma deformation, and the spin of the isomeric state of 141Ho

The nonadiabatic quasiparticle model for triaxial shapes is used to perform calculations for decay of 141Ho, the only known odd-Z even-N deformed nucleus for which fine structure in proton emission from both ground and isomeric states was observed. All experimental data corresponding to this unique case namely, the rotational spectra of parent and daughter nuclei, decay widths and branching ratios for ground and isomeric states, could be well explained with a strong triaxial deformation γ∼20°. The recent experimental observation of fine structure decay from the isomeric state, can be explained only with an assignment of I=3/2+ as the decaying state, in contradiction with the previous assignment, of I=1/2+, based on adiabatic calculations. This study reveals that proton emission measurements could be a precise tool to probe triaxial deformations and other structural properties of exotic nuclei beyond the proton drip-line.