When the separation between the highest occupied and the lowest unoccupied molecular
orbitals is not large, two alternative electronic states may be considered. The state
with two electrons paired up in the
HOMO is called a
low-spin state. The
low-spin state is the
ground state when the one-electron energy needed to promote an electron to the
LUMO is larger than the
Coulomb and
exchange repulsion energies required to pair up two electrons in the
HOMO.
Source:
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
https://doi.org/10.1351/goldbook.
