Valence Bond Treatment of Four-Electron Systems

VALENCE BOND TREATMENT OF FOUR-ELECTRON SYSTEMS 

We introduce a set of one-electron wavefunctions cf i, consisting of n orthonormal wavefunctions. For the binding orbitals we assume paired electrons and with an even number of electrons, we would look for functions which are eigenfunctions to the operator Sz with the eigenvalue 0, where Sz 

Using these expressions in the secular equation we obtain 

We furthermore have 5n = 522 = 4 and S12 = —2. The energy of the lowest state is finally obtained as 

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VALENCE BOND TREATMENT OF FOUR-ELECTRON SYSTEMS 197... 

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