Effective Hamiltonian formalism parameterization

Such splitting is called zero field splitting and indicated as ZFS. It adds up to the Zeeman energy. In the spin-Hamiltonian formalism, i.e. when the effects of the orbital angular momentum are parameterized, it is indicated as... 

Before the effective hamiltonian can be used in actual calculations some means must be found for expressing the terms Gcore [equation (33)] and the projection operator terms in equations (31) or (34) in a form which is convenient for computing matrix elements this is the subject of parameterization, which is dealt with in Section 3. Two other formal problems remain at this level. Firstly there is the need to modify equation (29) and, as a result, equations (31) and (34) if the atomic calculations on the separate atoms are of the open shell kind as is usually the case. In order not to bias the later molecular calculation the core operators and projection terms can be derived for some average of all the possible open-shell configurations,25 although care should be exercised in the choice of the hamiltonian for which the... 

Other semiempirical Hamiltonians have also been used within the BKO model. A Complete Neglect of Differential Overlap (CNDO/2) ° study of the effect of solvation on hydrogen bonds has appeared. o The Intermediate Neglect of Differential Overlap (INDO) °2 formalism has also been employed for this purpose.2011 Finally, the INDO/S model,which is specifically parameterized to reproduce excited state spectroscopic data, has been used within the SCRF model to explain solvation effects on electronic spectra.222,310-312 jhis last approach is a bit less intuitively straightforward, insofar as the INDO/S parameters themselves include solvation by virtue of being fit to many solution ultraviolet/visible spectroscopic data.29J... 

After having explained the relation between AIT and the LFT formalism, we now turn to a brief outline of the various parameterizations of V (p). The effective ligand field Hamiltonian (77) consists of one-electron terms, the one-electron ligand field Hamiltonian (vi>(/j). and two-electron terms (G(i,j)), which take account of the Coulomb interactions between the d-electrons summations is carried out over the d-electrons i <7 = 1, Nd. In difference to crystal field theory, these operators are left unspecified. Various LF models differ in the way they approxi-... 

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