Wolfsberg-Helmholz parameter

Some individual compounds have been studied using LCAO-MO theory in the Wolfsberg-Helmholz approximation (5). Although this method is somewhat more realistic and allows one to account for other properties (such as "charge-transfer bands, EPR, and NMR experiments) nevertheless, compared to the crystal field model it is much more laborious, it is only vahd for the individual case, and the choice of parameters in often rather arbitrary. 

According to the Wolfsberg-Helmholz formula (24), the /3 parameters can be regarded as diagonal terms of the CNDO Fock matrix. 

Thus, the strength of the interaction depends on the overlap S, and the other proportionality constant k - which has nothing to do with reciprocal space - is chosen as 1.75 it may also be an adjustable parameter. There is also a weighted, improved form of the Wolfsberg-Helmholz equation that helps to suppress so-called counterintuitive orbital mixing [113], a weakness of EH theory and also other minimum basis-set methods. 

This sequence is also established by comparing AOM parameters with the cor-responc g overlap integrals that are derived by substituting H l hi Eq. (4) using the Wolfsberg-Helmholz approximation [17]... 

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