The number of possible orientations, calculated as
, of
the spin angular momentum corresponding to a given total spin quantum
number
(), for the same spatial electronic wavefunction. A
state of singlet multiplicity has
and
.
A doublet state has
,
,
etc. Note that when
(the total orbital angular
momentum possible) there are only
orientations of total
angular momentum
possible.

Source:

PAC, 1996, *68*, 2223*
(Glossary of terms used in photochemistry (IUPAC Recommendations 1996))
* on page 2255