## Wikipedia - Diskussion:Hundsche Regeln (de) Wikipedia - Regole di Hund (it) Hund rules

https://doi.org/10.1351/goldbook.H02871
1. Of the different multiplets resulting from different configurations of electrons in @DT07018@ of an atom those with greatest multiplicity have the lowest energy (multiplicity rule).
2. Among multiplets having the same multiplicity, the lowest-energy one is that with the largest total orbital @A00353@ (@A00353@ rule) (valid if the total orbital @A00353@ is a constant of motion).
3. In configurations containing shells less than half full of electrons, the term having the lowest total @A00353@ $$J$$ lies lowest in energy, whereas in those with shells more than half filled, the term having the largest value of $$J$$ lies lowest (fine structure rule). Hund rules apply if the 'Russell–Saunders' @C01025@ scheme is valid. Sometimes the first rule is applied with questionable validity to molecules.
Source:
PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2246 [Terms] [Paper]