Two- and Three-Body Problems

Abstract

To determine the spin eigenfunctions for a system of two particles of spin (say, a neutron and a proton) which for a total spin vector operator

$$ S = \frac{\hbar }{2}\left( {\mathop \sigma \nolimits_n + \mathop \sigma \nolimits_p } \right) $$

((139.1))

simultaneously diagonalize its component S_z and its absolute square, S².