The concept of EPR is introduced with the case of free atoms. After this video, you will be able to draw qualitatively and quantitatively an energy level scheme for a free atom in an external magnetic field, for which you can then find the possible EPR transitions.
There are two tasks related to video:
First task: Use the forum underneath to describe what happens to a free La atom, subject to an external magnetic field, when it absorbs a microwave photon that satisfies the EPR resonance condition. As usual, feel free to comment respectfully on answers others have posted on the forum.
Second task: Consider the following picture that is taken from the video above:
Assuming a nuclear g-factor g=1, a nuclear spin I=1/2 and applied field B0=2 T, determine the photon energy for photons that will be absorbed in the case without hyperfine interaction. How does this photon energy change when there is a hyperfine interaction with Bhf=10 T? (consider transitions between the former mJ=-3/2 and -1/2 levels, and transitions between the former mJ=-1/2 and +1/2 levels)
Submit your answer on the forum underneath, and check it against other available answers there.