Crystal field charge transfer transition

Historically, crystal field theory was the first theoretical model (11, 86, 101, 123) used to explain d-d transition energies in metal complexes. Its usefulness is restricted to those complexes whose bonding is largely ionic, and its mqjor deficiency arises from its inability to account for charge transfer transitions. The iterative extended Hiickel and the ab initio, limited basis set, Hartree-Fock calculations are capable of de-... 

Fig. 2.21. Polarized electronic (optical) absorption spectra of a vivianite crystal with zones (labeled 1, 2, 3) exhibiting three different degrees of oxidation. The arrows identify Fe + crystal-field bands at 8,300 and 11,400 cm , and the Fe + —> Fe intervalence charge-transfer transition at 15,800 cm (after Amthauer and Rossman, 1984 reproduced with the publisher s permission).

Table 4.22. Optical spectral (one-electron) transition energies ( ) calculated for manganese oxides using the MS-SCF-ATa method, compared with experimentally observed transitions assigned to charge transfer, crystal field, valence band conduction band and crystal field conduction band transitions...

Only the d-d or crystal-field transitions are discussed here. Discussion of charge-transfer transitions, which require an MO description, is postponed to Section 20-18. 

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