Nucleons intrinsic angular momentum

Both protons and neutrons in the nucleus have an intrinsic angular momentum resulting from spinning of nucleons,... 

Since there exist two types of angular momentum, one caused by orbital movement of the individual nucleons and the other due to the intrinsic spin of the nucleons (internal angular momaitum), a more practical formulation of (4.8) is... 

The situation is complicated for nucleons as they carry both orbital angular momentum and intrinsic spin, leading to complex expressions for the g-factors. However, they can be calculated readily, and then compared to the observed values to make structural assignments. We will refer to the g-factors due to the individual nucleons as g, and to the g-factor due to the nucleus rotating as a whole as gR. Since only the protons contribute to the magnetic moment of the rotating nucleus we use gi Z/A as a good approximation [30]. 

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