Giant resonance are usually classified by three characteristic quantum number : L, S and T
Where, L= Orbital angular momentum
S= Intrinsic spin
L can have the values, 0, 1, 2, 3, …………………………..
The spin quantum no. S is either 0 or 1.
The isospin quantum no. T which is also either 0 or 1 (in this case)
T determines the relative behavior of protons and neutrons.
A giant resonance is called isoscalar giant resonance when T=0
ie; protons and neutrons oscillate in phase.
Example: electric monopole resonance (L= 0, S= 0, T=0).
Agiant resonance is called isovector giant resonance when T= 1,
ie; protons and neutrons oscillate with opposite phase.
Example: Gamow-Teller resonance (L= 0, S= 1, T= 1).