Question

What is the difference between half filled and partially filled orbital ?

Answer 1

• Half filled orbitals and partially filled both are same terms and both are used for those orbitals having half number of electrons (orbital have one electron).

• In short, the so-called Fermi correlation which is a consequence of
• the Pauli principle and applies only to electrons of the like spin keeps such electrons further apart comparing to the case of electrons of unlike spin.

• Naively one might think that a larger average distancebetween electrons of like spin reduces electron-electron repulsion energy which is the reason for the stability of high spin states.

• And while it is true that for each and every pair of electrons electron-electron repulsion energy is decreased as the average distance increases, it was shown that in the whole electron-electron repulsion energy for the molecular system in a high spin state is actually greaterthat in a lower spin spate