Spin-orbit interaction, lead spectroscopic

Spin-orbit interaction plays an important role in the electronic and spectroscopic properties of states arising from open-shell electronic configurations. Thus, the contribution of spin-orbit interaction to the ground state of Au is small but to Pb is large. Spin-orbit interaction not only splits the electronic state into substates but mixed states which would not mix in the absence of spin-orbit interaction. This is well illustrated by the lead atom. The ground state of the Pb atom would be P in the absence of spin-orbit... 

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