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Hyperfine Interactions and Lifetimes of Low-Energy States in W 182 and W 183 </…

1967; American Institute of Physics; Volume: 155; Issue: 4 Linguagem: Inglês

10.1103/physrev.155.1342

1536-6065

D. G. Agresti, E. Kankeleit, B. Persson,

Radioactive Decay and Measurement Techniques

The M\"ossbauer technique has been used to study the nuclear hyperfine interactions and lifetimes in ${\mathrm{W}}^{182}$ (${2}^{+}$ state) and ${\mathrm{W}}^{183}$ (${\frac{3}{2}}^{\ensuremath{-}}$ and ${\frac{5}{2}}^{\ensuremath{-}}$ states) with the following results: $\frac{g({\frac{5}{2}}^{\ensuremath{-}})}{g({2}^{+})}=1.40\ifmmode\pm\else\textpm\fi{}0.04$; $g({\frac{3}{2}}^{\ensuremath{-}})=\ensuremath{-}0.07\ifmmode\pm\else\textpm\fi{}0.07$; $\frac{Q({\frac{5}{2}}^{\ensuremath{-}})}{Q({2}^{+})}=0.94\ifmmode\pm\else\textpm\fi{}0.04$; ${T}_{\frac{1}{2}}({\frac{3}{2}}^{\ensuremath{-}})=0.184\ifmmode\pm\else\textpm\fi{}0.005$ nsec; ${T}_{\frac{1}{2}}({\frac{5}{2}}^{\ensuremath{-}})\ensuremath{\gtrsim}0.7$ nsec. These quantities are discussed in terms of a rotation-particle interaction in ${\mathrm{W}}^{183}$ due to Coriolis coupling. From the measured quantities and additional information on $\ensuremath{\gamma}$-ray transition intensities, magnetic single-particle matrix elements are derived. It is inferred from these that the two effective $g$ factors, resulting from the Nilsson-model calculation of the single-particle matrix elements for the spin operators ${s}_{z}$ and ${s}_{+}$, are not equal, consistent with the proposal of Bochnacki and Ogaza. The internal magnetic fields at the tungsten nucleus were determined for substitutional solid solutions of tungsten in iron, cobalt, and nickel. With $g({2}^{+})=0.24$ the results are: ${H}_{\mathrm{eff}}(\mathrm{W}\ensuremath{-}\mathrm{F}\mathrm{e})=\ensuremath{-}715\ifmmode\pm\else\textpm\fi{}10$ kG; $|{H}_{\mathrm{eff}}(\mathrm{W}\ensuremath{-}\mathrm{C}\mathrm{o})|=360\ifmmode\pm\else\textpm\fi{}10$ kG; $|{H}_{\mathrm{eff}}(\mathrm{W}\ensuremath{-}\mathrm{N}\mathrm{i})|=90\ifmmode\pm\else\textpm\fi{}25$ kG. The electric field gradients at the tungsten nucleus were determined for W${\mathrm{S}}_{2}$ and W${\mathrm{O}}_{3}$. With $Q({2}^{+})=\ensuremath{-}1.81 \mathrm{b}$ the results are: for W${\mathrm{S}}_{2}$, $eq=\ensuremath{-}(1.86\ifmmode\pm\else\textpm\fi{}0.05)\ifmmode\times\else\texttimes\fi{}{10}^{18}$ V/${\mathrm{cm}}^{2}$; for W${\mathrm{O}}_{3}$, $eq=(1.54\ifmmode\pm\else\textpm\fi{}0.04)\ifmmode\times\else\texttimes\fi{}{10}^{18}$ V/${\mathrm{cm}}^{2}$ and $\ensuremath{\eta}=0.63\ifmmode\pm\else\textpm\fi{}0.02$.