Why electrons must occupy degenerate orbitals with parallel spins?

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SUMMARY

Electrons occupy degenerate orbitals with parallel spins due to Hund's Rule, which states that maximizing the number of parallel spins minimizes electron-electron repulsion. This occurs because an antisymmetric wavefunction results in a zero probability of finding two electrons in the same position, thereby reducing Coulomb repulsion. The discussion also touches on the concept of exchange interaction, which further explains the stability associated with parallel spins in degenerate orbitals.

PREREQUISITES
  • Understanding of quantum mechanics principles
  • Familiarity with wavefunction symmetry
  • Knowledge of Coulomb repulsion in atomic systems
  • Concept of exchange interaction in quantum physics
NEXT STEPS
  • Study Hund's Rule in detail and its implications in atomic structure
  • Explore the mathematical formulation of antisymmetric wavefunctions
  • Research Coulomb repulsion and its effects on electron configurations
  • Investigate the concept of exchange interaction and its role in quantum mechanics
USEFUL FOR

Students of quantum mechanics, physicists, and chemists interested in atomic structure and electron configurations will benefit from this discussion.

tasnim rahman
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Why electrons occupy degenerate orbitals with parallel spins? heard something of stability due to exchange pairing of electrons. someone kindly clarify this matter.
 
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They needn't. This statement is known as Hunds rule and there are many exceptions known.
The usual argument behind Hunds rule is the following: If the spins are oriented parallel, the orbital part of the wavefunction has to be antisymmetric whence the probability to find two electrons at the same position is 0. This leads to a smaller coulomb repulsion than in a symmetric spatial wavefunction.
 
thank you very much. Just to be sure, what is this exchange pairing of electrons or exchange interaction?
 

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