CCL: Hund rule
- From: Steve Williams <willsd*|*appstate.edu>
- Subject: CCL: Hund rule
- Date: Thu, 21 Apr 2011 12:43:19 -0400
Sent to CCL by: Steve Williams [willsd__appstate.edu]
Here is a crude rationalization:
If electrons have parallel spins, they MUST occupy different spacial
orbitals, else the Pauli principle would be violated. Different
spacial
orbital occupation suggests reduced likelyhood of these electrons being
near each other, and so reduces the electron-electron repulsion. High
spin multiplicity implies low repulsion between electrons.
Of course more quantitative explanations involving exchange and Coulomb
contributions electron repulsion energy are available as well. Most
physical chemistry textbooks will a discussion of the 1s2s excited
configuration of He where this should be discussed.
Steve Williams
On 04/21/2011 11:23 AM, bonoit bonoit bonoit_10%x%yahoo.fr wrote:
Sent to CCL by: "bonoit bonoit" [bonoit_10 : yahoo.fr]
Dear CCLers,
I'm writting to enquire about the Hund rule:
"The term with the maximum multiplicity lies lowest in energy"
My question is:
What is the origin of this phenomenun?
Sincerely,
Bonoit>