Question

Hund’s rules can be used to determine the lowest energy term. They state that

1. The term with the largest S has the lowest energy. (This maximizes exchange stabilization.)

2. For terms with the same S, the term with the largest L has the lowest energy. (This minimizes spatial overlap.)

3. Spin-orbit coupling affects the energies of the levels as either

(a) highest J has the lowest energy, if the configuration is more than half full (of electrons) or

(b) the lowest J has the lowest energy, if the configuration is less than half full.

The rules are given in order of importance. In our case, the shell is less than half full. What term is lowest in energy according to Hund’s rules? (Note, really Hund’s rules are meant for ground state energies, not excited states, for which violations can occur, but we will use them anyway.)

Answer 1