Excited states of cerium (III) in various local symmetries by UV absorption and luminescence spectra

Abstract
Among trivalent lanthanides, cerium has the lowest-lying 5d^l configuration with up to five distinct Kramers doublet energies, strongly separated by chemical bonding of the same kind as known from Re, Os, Ir, Pt complexes with ground configuration 5d^q, but with more moderate spin-orbit coupling effects in Ce. Lanthanides rather indifferently show all the coordination numbers N from 6 to 12 (11 for CeF₃) and elastic internuclear distances. Stokes shifts can only be superficially rationalized with one configurational coordinate out of many.