Full MCVB

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. 

When these orbitals are optimized, the energies of the SCVB wave functions are higher, of course, than those of the full MCVB wave functions. We show the differences at the equilibrium and infinite intemuclear separations in Table 10.6. The energy curves are parallel within s 0.1 eV, but the SCVB energy is about 1.1 eV higher. 

A full MCVB calculation on BeH with the above basis yields 504 doublet standard tableaux functions, and these combine into 344 symmetry functions. In Table 10.7 we give some details of the results with experimental values for comparison. The calculated is within 0.1 eV of the experimental value, the values of... 

The addition of the doubly ionic structures to the MCVB wave function produces an energy only 0.15 eV above the full calculation and, therefore, has produced just about all the necessary delocalization. 

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