The classically expected value of the gyromagnetic ratio has to be corrected for quantum mechanical and relative effects. A correction factor g is introduced:

with Bohr's magneton

For an electron this factor can be calculated to a high accuracy following Dirac's theory [1].

In the same way a correction on the gyromagnetic ratio of the nuclei can be applied:

, with the nuclear magneton .

In this case the inner structure of the nucleus and the structure of protons and neutrons (Protons are build out of quarks and are surrounded by a plasma made of quarks and gluons ) has to be taken into account [2]. At that moment the inner structure is not well known. The g-factors for nuclei have to be determined experimentally.

Biblography:

1. Kap. Radiative Corrections to the Interaction with an External Field In: Itzykson, Claude; Zuber, Jean-Bernard: Quantum Field Theorie, McGraw-Hill, International Edition 1980, S.347
2. Kap. Der Aufbau der Hadronen In: Berger, C.: Teilchenphysik, Springer, 1992, S.135