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Homework Help: Angular Momentum of Photon

  1. Jan 26, 2005 #1
    Currently working on a problem about Zeeman Effect. Consider two states, 3S1 and 3P1, each of which is a triplet under the effect of an external B field in the z direction. 3P1 is the ground state.

    If we shine a beam of circular polarized light, incident along a direction parallel to the B field, to the atoms, it is said that only 2 absorption lines among the 7 allowed transition lines (considering only dipole radiation) will be observed.

    The answer says that only two lines are observed because the photon carry 1 unit of angular mometum, hence only those lines with (delta Mj)=1, namely the Mj=1 and Mj=0 states of 3S1, can be seen. I have 3 questions:

    1. What is the proof of the claim that "photon carry 1 unit of angular mometum"?
    2. What is the significance of having circular polarized light in this particular problem?
    3. How can we, if possible after all, excite the atoms to the remaining state?(i.e. Mj=-1 of 3S1 state)
  2. jcsd
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