Valence-bond method physical significance

These results brings all phenomenologieal eonelusions from the valence bond method, now having the and q>g with the physical significances of the atomic orbitals, for the atoms A and B, respectively. This way, the bonds that a biatomic molecular system may establish are consequently reahzed through different MO listed as ... 

One problem with the network equations is that they can, on occasion, give rise to negative bond valences which have no physical significance (expect to indicate that, from a chemical point of view, the bond should not exist). Rutherford (1998) has explored the resonance bond model as an alternative to the use of the loop equation (Section 14.4) while Rao and Brown (1998) have suggested using the method of maximum entropy (Section 11.2.2.1). 

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