Configuration state parameters can be used to estimate it, and a decrease in this interaction upon ligand binding causes the nephelauxetic effect.
Configuration state parameters can be used to estimate it, and a decrease in this interaction upon ligand binding causes the nephelauxetic effect. A set of three parameters A, B, C which reflect this interaction are named for Racah, one of which  normalizes both axes of a Tanabe-Sugano diagram. This interaction is responsible for the difference between the actual energy of a system and the Hartree-Fock energy, which is why post-Hartree-Fock methods attempt to calculate it. The presence of a term for this interaction in the Schrodinger equation of a helium atom makes it non-separable, and this interaction breaks the degeneracy of orbitals with the same principal quantum number but different angular momentum quantum numbers. This interaction is the basis for Hund's rule, which states the particles involved fill up orbitals one at a time. For 10 points, name this repulsion between negative particles.
Configuration state parameters can be used to estimate it, and a decrease in this interaction upon ligand binding causes the nephelauxetic effect.
{Electron}-{electron} repulsion or {electron correlation} or {Columb}[{ic}] repulsion (accept anything that {implies} that {electrons repel} or {interact} with {each} other)