Mixed alignment in the osmium-iridium region

It is shown that in rare cases, backbending in high-spin nuclei may be due to the alignment of a pair of like nucleons occupying different high-j orbitals, unlike the normal case, in which they occupy the same orbital. This mixed alignment has special implications for the blocking effect in adjacent odd nuclei, as exemplified by ${}_{}{}^{180}{}_{}{}^{}\mathrm{Os}$ and its neighbor ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ir}$. Finally, to get the correct order of the two backbends in ${}_{}{}^{180}{}_{}{}^{}\mathrm{Os}$ requires changes in the conventional Nilsson parameters for protons.