Isotope effects of samarium and ytterbium in the acetate/amalgam separation system

The data on the fractionation of all stable isotopes of ytterbium and samarium in a Me(III) acetate/Me amalgam system were obtained. The light isotopes were preferentially fractionated into the amalgam phase. The single separation gains per mass difference were found to be in the range (4.90/17.8) x 10-4 for ytterbium and (2.2/3.8) x 10-4 for samarium. The divergence from the linear dependence between separation gains and isotope mass differences was observed and explained as the effect of nuclear field shift and nuclear spin effects. The maximum value of εu.m. was observed to be 17.8 x 10-4 for the lightest, neutron deficit isotope of ytterbium, 168Yb. The same value for the lightest isotope of samarium, 144Sm, with a magic number of neutrons (82), was close to the mean for other isotopes. (author)