Density-Functional Calculations for Ozone: Striking Results for an Important Molecule

Density-functional calculations have been performed for low-lying states of ozone (${\mathrm{O}}_3$) with use of a local-density approximation for exchange and correlation. The energy surfaces are qualitatively better than Hartree-Fock results and in generally good agreement with experiment and configuration-interaction calculations where available. As in $\mathrm{sp}$-bonded solids and diatomic molecules, there is a substantial overestimate of the dissociation energy. This suggests caution in interpreting local-density calculations of bonding energies in general, particularly if local bonding effects are important.