Hyperfine interactions between electrons

Abstract

The relativistic Breit Hamiltonian between electrons is transformed into an effective vector potential ${\mathbf{A}}_i$ for the $i.$th electron, ${\mathbf{A}}_i$ having the structure of a recoil--corrected hyperfine operator. Apart from a small three--body operator, the Dirac--Breit equation is now easier applied to relativistic magnetic properties of complex systems.

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