About the spin moments

Electron and nuclear magnetic moments can be regarded as arising from a property of the particles, i.e. that they possess an intrinsic angular momentum as if they were spinning. Such angular momenta are given by 

The projection of S and I along a z direction (defined by an external magnetic field or otherwise) are +xh or — V2 (Fig. 1.6). Thus we have two wavefunctions, one with S (or /) = V2 and with a component along z — V2 and another with S (or /) = V2 and with a component along z = — V2. 

The component is indicated in quantum mechanics as Ms or M/. The notation to indicate the wavefunction is thus 

Physically, it means that it is possible to know simultaneously the square of the intensity of the spin angular momentum and its component along z. Since the spin wavefunctions are not eigenfunctions of the operators S or /, it is impossible to 

The intrinsic angular momentum S is related to the intrinsic magnetic moment Ps through the relation 

---