Das Quadrupolmoment des 8,42 keV-Niveaus von Tm169

The hyperfine interaction of the 8·42 kev level of Tm169 was investigated using the Mossbauereffect in Tm-ethylsulfate. The hyperfine-splitting is of pure quadrupoletype; its temperature dependance between 6°K and 250°K was measured. The spectroscopic quadrupolemoment of the 8·42 kev level was determined asQ=−(1·1±0·1) barn, leading to an intrinsic quadrupolmoment ofQ0=+(5·5±0·5) barn.