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Atomic transition - What does this notation mean?

  1. Aug 12, 2006 #1
    Hello all, I've been reading about laser cooling, and when they speak of tuning the laser to a atomic transition, they write this (for example) as
    "The laser cooling was performed on the [tex]D_2[/tex] transition ([tex]3S_{1/2} \rightarrow 3 P_{3/2}[/tex])".

    But what do they mean by that notation? I'm clueless as what it is supposed to mean as it doesn't look like the spectroscopic notation (i.e the number 3 is NOT in superscript).
    Best regards,
  2. jcsd
  3. Aug 12, 2006 #2


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    Staff Emeritus
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    I believe that the 3 is the principal quantum number, S and P are related to the suborbtial or azimuthal quantum number, and 1/2 and 3/2 are (IIRC) the total electronic angular quantum momentum numbers which parameterize the total angular momentum of a given electron, by combining its orbital angular momentum and its intrinsic angular momentum (i.e., its spin).

    Has one studied the quantum numbers of atomic electrons?
  4. Aug 12, 2006 #3
    ok so the
    [tex]3 S_{1/2} \rightarrow 3 P_{3/2}[/tex]
    means the same as for a normal transition, except that this is in the case of a composite system? i.e the transition is L=0 to L=1 and J=1/2 to J=3/2.

    What is then meant by [tex]D_2[/tex]? And how does this relate to the above?
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