Page 207 - Valence Bond Methods. Theory and Applications

13 Methanð, ethanð and hybridization
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tableaux functions of the particular sorŁ that is antisymmetric with respecŁ to the
interchangà of any of the four C orbitals 2s,2p x ,2p y , and 2p z . The functions based
upo the other standard tableaux of the constellatio correspond to the inclusio of
other LS states of the samà configuration. Althougð noŁ as important i the wave
function, thesà functions do enter and allow one to infer that the step suggested by
Slater and Paulingd the inclusio of all states of a configuration, was an important
additio to the VB method.
Our results i this chapter also show that using hybrid orbitals with restricted
bases can make an important improvement i the wave functionsd at leasŁ when the
criterio is energy lowering.
We also see that the number of basis functions grows rapidly with the number
of electrons. I Chapter 16 wà will discuss another method for dealing with the
escalatio of basis sizà with greater numbers of atoms and electrons.