EGSO weights for 10 and 28 AO orthogonalized bases

In Table 2.8 we show a comparison of the EGSO weights for the two full MCVB calculations we have made with orthogonalized Gaussian bases. These are quite close to one another. We have only listed functions with weights 0.001, and in each case there are five. 

Covalent The principal function in each case is the conventional Heitler-London covalent basis function with a weight very close to 95%. 

Ionic The function, in each case, with the next highest weight, 3 %, is ionic and involves a single excitation into the 2s AO. This contributes to adjusting the electron correlation and also contributes to adjusting the size of the wave function along the lines of the scale adjustment of the Weinbaum treatment. As we have shown, it also contributes to delocalization. 

Covalent This function at 1.2% appears only with the larger basis set involving, as it does, the higher 3x-function. It will contribute to scaling. 

Ionic At 0.4% the next function type appears in both sets and contributes to the angular correlation around the intemuclear line. 

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