$\nu i_{\frac{13}{2}}$ and $\nu h_{\frac{9}{2}}$ isomers in odd-$A$ Pt nuclei

${\frac{13}{2}}^{+}$ isomers with half-lives of 311 ± 15, 143 ± 5, and 95 ± 5 μs in ${}_{}{}^{187}{}_{}{}^{}\mathrm{Pt}$, ${}_{}{}^{189}{}_{}{}^{}\mathrm{Pt}$, and ${}_{}{}^{191}{}_{}{}^{}\mathrm{Pt}$, respectively, have been observed in ($\alpha ,3n\gamma$) reactions on isotopically enriched Os targets. Isomeric decay schemes based on the present measurements and on ${}_{}{}^{189}{}_{}{}^{}\mathrm{Au}$ and ${}_{}{}^{191}{}_{}{}^{}\mathrm{Au}$ decay data are presented. It is proposed that the ${}_{}{}^{187,189,191}{}_{}{}^{}\mathrm{Pt}{\frac{13}{2}}^{+}$ isomers deexcite by $M2\mathrm{}$ transitions to ${\frac{9}{2}}^{-}$ intrinsic states of $\nu h_{\frac{9}{2}}$ character. In $A\ge 193$ Pt nuclei the corresponding ${\frac{9}{2}}^{-}$ states must lie above the known $\nu i_{\frac{13}{2}}$ isomers, which have much longer half-lives.