Two-quasiproton states inOs190andOs192studied with the (t,α) reaction

Level structures up to 3000 keV in ${}_{}{}^{190}{}_{}{}^{}\mathrm{Os}$ and ${}_{}{}^{192}{}_{}{}^{}\mathrm{Os}$ have been studied using the ${}_{}{}^{191}{}_{}{}^{}\mathrm{Ir}$ and ${}_{}{}^{193}{}_{}{}^{}\mathrm{Ir}$ ($t$,$\alpha$) proton pickup reactions with 15 MeV tritons. The $\alpha$-particle spectra were obtained with the quadrupole-dipole-dipole-dipole magnetic spectrometer with peak widths of ∼11 keV (full width half maximum). This reaction strongly excites the $I,K^{\pi }=4,4^{+}$ levels at 1162 keV in ${}_{}{}^{190}{}_{}{}^{}\mathrm{Os}$ and at 1070 keV in ${}_{}{}^{192}{}_{}{}^{}\mathrm{Os}$, which were previously interpreted as two-phonon $\gamma$-vibrational states. The large two-quasiproton amplitude is reasonably explained by assuming single-phonon hexadecapole vibrations which involve the $\left\{\frac{5}{2} \mathrm{}\right[402], \frac{3}{2} \mathrm{}[402\left]\right\}$ configuration. Many two-quasiproton states are observed in the energy region 2000-3000 keV. The strongest peaks found at an excitation energy of ∼2600 keV in both ${}_{}{}^{190}{}_{}{}^{}\mathrm{Os}$ and ${}_{}{}^{192}{}_{}{}^{}\mathrm{Os}$ may be the remaining portions of the two-quasiproton ${\left\{\frac{5}{2} \mathrm{}\right[402], \frac{3}{2} \mathrm{}[402\left]\right\}}_{I,K^{\pi }=4,4^{+}}$ states.