Abstract
The properties of angular momentum and its connection to magnetic
momentum are explored, based on a reconsideration of the Stern-Gerlach
experiment and gauge invariance. A possible way to solve the so called
spin crisis is proposed. The separation of angular momentum of a quan-
tum system of particles into orbital angular momentum plus intrinsic angular momentum is reconsidered, within the limits of the Schrodinger
theory. A proof is given that, for systems of more than two particles, un-
less all of them have the same mass, the possibility of having eigenvalues
of the form (n + 1/2)h is not excluded.