# What is the Landé g factor?

What is the Landé g factor?

I know that it gives the relation between magnetic moment and angular moment, but i wanted to know why are those magnitudes related to each other and why is the magnetic moment operator defined proportional to he angular moment and how is the gyromagnetic ratio calculated theoretically.

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I can't answer your question however the actual calculation of the g factor could be done via Wigner-Eckart theorem – Jorge Nov 13 '12 at 22:04
My impression is that this comes from accepting the non-existence of magnetic monopoles. Since this is the case, the magnetic momentum of electrons has to come from certain rotation, or intrinsic angular momentum. If not, they would be magnetic monopoles by having angular moment without charge movement. Hence the spin is taken as the fundamental property rather than the intrinsic magnetic moment, however we can only measure spin, and I cannot see how could we measure angular momenta of particles without them having magnetic moment. But it makes me wonder if this is really true. – rmhleo Sep 14 '15 at 9:17