Note: We are dealing with perturbation on the states $|nlm_lm_s>$ where n is the principle quantum number, l is the angular momentum quantum number, and $m_l$ and $m_s$ are the eigenvalues of $L_z$ and $S_z$ corresponding to this particular eigenstate. j is the Total angular momentum quantum number: $j = l \pm 1/2 $.

In page 275 of Griffiths, he finishes the derivation of the energy perturbation due to the fine structure correction. He then says that the fine structure breaks degeneracy in l but not in j. Why is this? It seems to me that the degeneracy in j is broken, and that there is still degeneracy in l.

Griffiths Text


1 Answer 1


In my 1995 edition the text (on page 242) reads:

1995 edition

So presumably this is an error in whatever edition you have.

  • $\begingroup$ Thanks. I would upvote, but I have not the reputation to do so. $\endgroup$ Commented Oct 3, 2014 at 1:32
  • $\begingroup$ @ZaneDufour: if this answers your question please click on the tick symbol to accept the answer. $\endgroup$ Commented Oct 3, 2014 at 4:55
  • $\begingroup$ Sadly, the 3rd edition (2018) reverted back to the error reported by @ZaneDufour $\endgroup$ Commented Jul 20, 2021 at 10:06

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