Intervalence charge transfer

In chemistry, intervalence charge transfer, often abbreviated IVCT or even IT, is a type of charge-transfer band that is associated with mixed valence compounds. It is most common for systems with two metal sites differing only in oxidation state. Quite often such electron transfer reverses the oxidation states of the sites. The term is frequently extended to the case of metal-to-metal charge transfer between non-equivalent metal centres.^[1] The transition produces a characteristically intense absorption in the electromagnetic spectrum. The band is usually found in the visible or near infrared region of the spectrum and is broad.

The process can be described as follows:

L_nM⁺-bridge-M'L_n + hν → L_nM-bridge-M'⁺L_n

where L is a bridging ligand.