a). Lowest energy MO:
b). Highest energy MO:
This can changes based on the basis set used.
c). Lowest energy \( \pi\) MO:
- The lowest MO has density around the individual carbon atoms, like a superposition of s-orbitals; this means this MO is really a combination of non-bonding 1s atomic orbitals. There are no nodes, but the probability densities between the carbon are low.
- The highest MO has density shifted away from between the carbon atoms, outward from the ring and away from all nuclei.
- The lowest \(\pi\) orbital has density above and below the plane of the carbon ring, delocalized over all the carbons.
The lowest MO has an energy of -11.3 hartrees which is -7046 kJ/mol.