# Derivation of an angular momentum expression

• I
• Malamala
Malamala
Hello! I found this formula in several places for the total angular momentum of a particle with intrinsic spin 1/2 and angular momentum l=1 in the non-relativistic limit:
$$\frac{1}{\sqrt{4 \pi}}(-\sigma r /r )\chi$$
where ##\sigma## are the Pauli matrices and ##\chi## is the spinor. Can someone point me towards a derivation of this? Also can this be generalized to other s and l (or at least other l for s=1/2), can someone point me towards that, too, if that is the case? Thank you!