Abstract
Two anomalously weak transitions within the manifolds in have been identified. Their transition strengths are measured to be 1000 times weaker than that of the strongest transition in the same group. This dramatic suppression of transition strengths is due to the dominance of the hyperfine interaction over the fine-structure interaction. An alternative selection rule based on coupling (where the nuclear spin is first coupled to the total electron spin) is proposed. This provides qualitative understanding of the transition strengths. It is shown that the small deviations from the coupling model are fully accounted for by an exact diagonalization of the strongly interacting states.
- Received 28 August 2008
DOI:https://doi.org/10.1103/PhysRevLett.101.173001
©2008 American Physical Society