LIGAND-METAL OVERLAP AS SOURCE OF INTENSITY FOR LIGAND-FIELD AND CHARGE-TRANSFER TRANSITIONS

Experimental evidence for a strong decrease of intensities in both ligand field and charge transfer spectra with increased metal-ligand distance is presented. It suggests that overlap of charge clouds for metal ion and ligands is a major source of their intensities. The polarization ratios in noncubic crystals also appear to be largely determined by differences in bond lengths. Data from the literature are consistent with this interpretation. Potential applications of this still tentative principle for the gathering of structural information on pure and doped crystals as well as on amorphous systems are discussed. © 1979.