# A Hund's rule and strong spin-orbit interacion

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1. Dec 31, 2016

### Abigale

Hi,
I have read that Hund's rules are valid for Atoms with low z.
Because the third Hund's rule is build of Russell-Saunders coupling.

Can I still use the first and second Hund's rule for heavy atoms and jj-coupling( for the third rule)?
Or how can I know the groundstate for an atom with large spin-orbit interaction?

Thank you
Abby

2. Dec 31, 2016

### TeethWhitener

I suppose you could, but it'll be meaningless, because $\textbf{L}$ and $\textbf{S}$ are not good quantum numbers in the presence of large spin-orbit coupling. You might take a look at the Wikipedia entry for term symbols:
https://en.m.wikipedia.org/wiki/Term_symbol
It has a good overview for how we determine term symbols for jj coupling.

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