Metal ligand-field state

Table 1 The excitation energies (eV) to the lowest-energy metal-to-ligand charge transfer and ligand field states...

As a transition metal with a partially filled d-subshell of electrons, the UV-Vis spectroscopy of iron is a sensitive measure of both the first coordination shell environment (ligand field), and oxidation and spin state of the metal. Ligand field bands are an excellent experimental handle for spectroelectrochemistry, and in the case of heme proteins the Soret band provides an additional probe for... 

A large number of recent examples exist for luminescence from metal systems such as copper(I), which can have no ligand field states. The interest in the photophysics of copper(I) complexes is sparked by the many possible coordination geometries and structures that are accessible since the coordinated metal imposes no electronic constraints to bonding and concomitant resulting variety of excited states that are observed. ... 

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