g=1, I=1/2, B_0=2T
1) Without hf interaction:
E(m_J)=-g_J \mu_B B_0 m_J
=> E_photon = \Delta E=-g_J \mu_B B_0 \Delta m_J
-Case of transition between m_J=-3/2 and m_J=-1/2:
E_photon,1= -g_J \mu_B B_0 (-1) = 0.16 meV.
-Case of transition between m_J=-1/2 and m_J=+1/2:
E_photon,2= -g_J \mu_B B_0 (-1) = 0.16 meV.