Relation between E2 transitions in even–even and odd-mass nuclei

How is the B (E2; 2 + 1 → 0 + 1 ) value in an even-even nucleus related to corresponding B (E2; J i → J f ) values in a neighbouring odd-mass nucleus? If either neutrons or protons are confined to a single- j orbital and if the nucleon-nucleon interaction conserves seniority, a simple relation between the two properties is obtained, which may differ from what is found in the weak-coupling limit of the core-particle model. This single- j relation is substantially perturbed if several non-degenerate orbitals are considered. An application to recently measured B (E2) values in neutron-deficient tin isotopes is presented.