Irreducible tensor form of the relativistic corrections to the M1 transition operator

Abstract

The relativistic corrections to the magnetic dipole moment operator in the Pauli approximation were derived originally by Drake (1971 Phys. Rev. A 3 908). In the present paper, we derive their irreducible tensor-operator form to be used in atomic structure codes adopting the Fano–Racah–Wigner algebra for calculating its matrix elements.