3. Electronic energy of diatomic molecules

3.1 Construction of molecular orbitals

Assuming the validity of the Born-Oppenheimer approximation, we solve the Schrödinger equation for electrons in the field of the two nuclei. The central field method is obviously inappropriate for two centers of force, but we can always use the self-consistent field approach: we assume an initial wave function involving the two atoms A and B; we use the resulting electronic distribution to calculate a potential distribution; we solve the Schrödinger equation with this potential to find a new wave function and so on... The energy values found in this way can be used to draw potential curves like the one shown (solid blue line called the "binding" curve) in figure