Lanthanides and actinides are known to have deformed nuclei, which cause the charge distribution effects in the isotope shifts of the atomic emission spectral lines. Therefore, the field shift is expected to have a great effect on their isotope effects. In case of Cd, The contribution of the nuclear field shift effect to the observed isotope enrichment factor was estimated to be 5–30% [22]. Another supporting proof for the importance of the field shift on isotope effects was given by the study of temperature effect on Eu isotope effects. It was shown that the separation coefficient of Eu isotopes increases with the increase in temperature, which could be explained by the field shift effects [13].