L= O, 1,
2, 3,
4, 5,
= S, P, D, F, G, H,
J = L+S; S= O or 1
2S+1LJ
When S =0,
2S+1 =1, Singlet States
When S=1,
2S+1=3, triplet States
L= 0, 2, 4,
Even States
L= 1, 3, 5,
Odd States
1S0 , 1D2 , 1G4,
are
leading even singlet states
1P1 , 1F3 , 1H5 ,
are leading odd singlet states
3S1-3D1 is the most interesting example of a coupled triple state. It has the only bound NN Statethe deuteron.