Static Quadrupole Moments of the First2+States of the Even-Even Osmium Nuclei

Measurements of the total thick-target yields of $\gamma$ rays deexciting the first $2^{+}$ excited states of ${\mathrm{Os}}^{192,190,188,186,184}$ following Coulomb excitation by helium, oxygen, and sulfur ions have been made. These measurements were compared with theoretically calculated yields in order to extract linear combinations of the static electric quadrupole moments of the $2^{+}$ states. The results were compared with the measurements of Pryor and Saladin of the absolute moments of ${\mathrm{Os}}^{192,190,188}$ in order to obtain the best combined values for these three isotopes, as well as absolute values for ${\mathrm{Os}}^{186,184}$. These values are -0.50 ± 0.20, -0.95 ± 0.19, -1.32 ± 0.43, -1.47 ± 0.54, and -2.4 ± 1.1, respectively. For the isotopes ${\mathrm{Os}}^{192,190,188,186}$ the $B(E2,0^{+}\to 2^{+})$ values determined in the experiment agree with published values to within 10%. The $B(E2,0^{+}\to 2^{+})$ value of ${\mathrm{Os}}^{184}$ was previously unknown and was determined to be 3.20 ± 0.62 ${\mathit{e}}^2$ ${\mathit{b}}^2$. The results are also compared with the model calculations of Kumar and Baranger and found to be in good agreement.