Level structures up to 3000 keV in Os190 and Os192 have been studied using the Ir191 and Ir193 (t,α) proton pickup reactions with 15 MeV tritons. The α-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,Kπ=4,4+ levels at 1162 keV in Os190 and at 1070 keV in Os192, which were previously interpreted as two-phonon γ-vibrational states. The large two-quasiproton amplitude is reasonably explained by assuming single-phonon hexadecapole vibrations which involve the {52 [402], 32 [402]} 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 Os190 and Os192 may be the remaining portions of the two-quasiproton {52 [402], 32 [402]}I,Kπ=4,4+ states. NUCLEAR REACTIONS Ir191,193(t,α) Os190,192, Et=15 MeV: measured σ(Eα); enriched targets; analyses, DWBA including the (t-α-α′) channel, the strong coupling model, RPA.
