Let's say you take a beam of particles and pass it through a Stern Gerlach apparatus and you select one of the outgoing beams, therefore collapsing the wavefunction to certain values of orbital angular momentum and spin angular momentum. If you performed the Zeeman experiment on that beam, I'm assuming you wouldn't see any splitting because the particles in this beam have very well defined orbital and spin angular momentum? Assuming they all have the same quantum number n. For example in the anomalous Zeeman effect the splitting occurs from the quantum number [itex]m_j[/itex], where j is the total angular momentum, correct? So since we have a very well defined value for j, there shouldn't be any splitting in that case. Is this reasoning correct?