## spin projection

https://doi.org/10.1351/goldbook.ST07106
A component, $$M_{S}$$, of the angular spin moment $$S$$ along an arbitrary axis (usually chosen as the z-direction). $$M_{S}$$ can take the values between $$-S$$ and $$S$$: $$-S$$, $$-S+1$$,..., $$S- 1$$, $$S$$. The term is also used to denote an operation (spin-symmetry projection) allowing one to eliminate @ST07103@ in the cases where wavefunctions are not eigenfunctions of the operator $$S^{2}$$.
Source:
PAC, 1999, 71, 1919. (Glossary of terms used in theoretical organic chemistry) on page 1963 [Terms] [Paper]