Observation of knight shifts in metallic tungsten and tantalum with the 6.2 keV181Ta Mössbauer resonance

Completely resolved Mössbauer spectra for the 6.2 keV¹⁸¹Ta transition were measured at R.T. in external magnetic field of 2.8 and 4.4 kOe for¹⁸¹Ta impurities in W- and Tametal respectively. A more precise mean value for theg-factor ratiog _9/2/g _7/2 of 1.797(3) was obtained. The magnetic moment of the 6.2 keV-state was determined to be +5.47 (2) n.m. From the hyperfine fields at the¹⁸¹Ta-nuclei in W a Knight-shift of 2(1)% and in Ta of 1.7(8)% was deduced. For the spectrum of the magnetically splitted Ta-metal absorber a reduced dispersion parameter of 2ξ=20(2) was measured, while the linewidth showed only a slight narrowing.