Hay-Thibeault-Hoffmann

Keywords Superexchange Magnetic orbital Anderson model Hay-Thibeault-Hoffmann model Kahn-Briat model... 

Eq. 3.7 and the 5 = 1 state using Eq. 3.2. Which state is the ground state, singlet or triplet, depends on the magnitudes of the two electron integrals Jaa, Jab and Kat-Summarizing A Full Cl treatment of two electrons in two orbitals in a symmetric system leads to Eq.3.7 for 5 = 0 and to Eq.3.2 for 5 = 1. This approach forms a basis for the Hay-Thibeault-Hoffmann (HTH) model discussed in Chap. 4. 

The theory of inter-atomic exchange intoactions (super-exchange) has been reviewed in many excellent articles see for instance Anderson (24), Martin (25), and Ginsberg (26) and the book edited by Willet, Gatteschi, and Kahn (27). Hay, Thibeault and Hoffmann (28) and Kahn and Briat (29) have developed theories which view the exchange interactions fiom a molecular orbital perspective. 

The theoretical expression which can be derived for J within the framework of the Hay, Thibeault and Hoffmann orbital model2977 is... 

Hay, Thibeault, and Hoffmann showed that /af can be analyzed in terms of pairwise interactions of dimeric molecular orbitals with the square of the splitting in energy between the members of a pair being a measure of the stabilization of the low-spin state. Their final result... 

The second valence-only model starts from a molecular orbital viewpoint and was derived in the mid 1970s by Hay, Thibeault and Hoffmann (HTH) [2], approximately at the same time as the Kahn-Briat model. The magnetic orbitals are defined as linear combinations of orthogonal atomic-like orbitals... 

Hay PJ, Thibeault JC, Hoffmann R. 1975. Orbital interactions in metal dimer complexes. J Am Chem Soc 97 4884-4899. 

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