spin-orbit coupling

The interaction of the electron spin magnetic moment with the magnetic moment due to the orbital motion of the electron. One consequence of spin-orbit @C01025@ is the mixing of zero-order states of different multiplicity. This effect may result in fine structure called @S05872@.
PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2277 [Terms] [Paper]