Modelo de Piepho-Krausz-Treasure

The Piepho-Krausz-Schatz or PKS model applies to mixed valence systems with vibron coupling, especially transition coordination compounds.

This model, first exposed by Susan B. Piepho, Elmars R. Krausz and P. N. Schatz in 1977 takes into account the most symmetrical, "breathing" vibrations around the electroactive centers. The main contribution on the Hush model, above, is that with the PKS model we obtain own functions and explicit eigenvalues ​​(it is a Hamiltonian model). Thus, in addition to the position and intensity of the interval band, it is possible to calculate its structure and shape, as well as other properties, such as EPR spectrum, magnetic properties, or the degree of electronic offshoring.

The approach of the ligands becomes more unfavorable energetically if in the center there is an "extra" electron. Thus, the PKS vibronic coupling competes with electronic transfer, and has a locator effect.

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