Question

The Russel-Saunders coupling is not valid for actinides. What coupling scheme could be more appropriate actinides and why?

Answer 1

The Russel-Saunders coupling is mainly applied to the light atoms with atomic number less then 57. To get some better wave function approximation, j-j-coupling must be applied. Thus, actinides possess atomic numbers from 89 to 103 and this is definitely higher than 57.