** **

**In systems with multiple
electrons within an LS coupled subshell, terms with high S and
low L tend be the most tightly bound.
**

** **

**Low L means elliptic orbits,
which spend more time close to the nucleus.**

** **

**WHY HIGH S ?**

** **

**High values of S occur
when the electron spins are aligned (all have the same m_{s}),
causing the spin portion of the wave function to be symmetric. **

** **

**The space portion of the wave
function must then be antisymmetric, and the Pauli exclusion principle prevents
the equivalent electrons from occupying the same region of space. **

** **

**Thus the inter-electron
repulsion is reduced thereby increasing the binding. **

** **

**CONCLUSION: A Bose condensation in spin-space produces a
Pauli exclusion in configuration space.
**

** **

** **

**WHEREAS FOR LOW S,**

** **

**For systems with low S, the
spins are anti-aligned pairwise, with anti-symmetric wave functions. **

** **

**Thus the spatial wave function
is symmetric and the equivalent electrons can overlap in space, increasing
their repulsive interaction. **

** **

**CONCLUSION: A Pauli exclusion in
spin-space produces a Bose condensation in configuration space.**

** **

** **

The high S of the ground state
has implications in, eg, the high spin magnetism in the partially filled 3d
shell of ferromagnetic atoms.