Hyperfine Interactions and Lifetimes of Low-Energy States in W182 and W183

Abstract

The Mössbauer technique has been used to study the nuclear hyperfine interactions and lifetimes in W182 (2+ state) and W183 (3/2- and 5/2- states) with the following results: g(5/2-)/g(2+)=1.40±0.04; g(3/2-)=-0.07±0.07; Q(5/2-)/Q(2+)=0.94±0.04; T1/2(3/2-)=0.184±0.005 nsec; T1/2(5/2-)≳0.7 nsec. These quantities are discussed in terms of a rotation-particle interaction in W183 due to Coriolis coupling. From the measured quantities and additional information on γ-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 sz 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: Heff(W-Fe)=-715±10 kG; |Heff(W-Co)|=360±10 kG; |Heff(W-Ni)|=90±25 kG. The electric field gradients at the tungsten nucleus were determined for WS2 and WO3. With Q(2+)=-1.81 b the results are: for WS2, eq=-(1.86±0.05)×10^18 V/cm^2; for WO3, eq=(1.54±0.04)×10^18 V/cm^2 and η=0.63±0.02.

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