For the case without hyperfine interaction, the photon energy is given by Delta_E = g mu_B B_0. Which is equal to 1.1577*e-4 eV.
If hyperfine interactions are included, the energy change is given by Delta_E_hyp = Delta_E – A*(m_J1*m_I1 – m_J2*m_I2). Depending on the sign of m_I one of the following two energies will be possible:
– Delta_E_hyp (-1/2) = 1.1566*e-4 eV
– Delta_E_hyp (+1/2) = 1.1587*e-4 eV