The performance of density functional theory for equilibrium molecular properties of symmetry breaking molecules

The reliability of density functional theory (DFT) for the prediction of eq uilibrium molecular properties is assessed for several challenging molecule s (F-2(+), O-2(+), O-2, O-4(+), F-4(+), and NO3) which tend to artifactuall y break spatial symmetry in the Hartree-Fock approximation. DFT appears to be among the more robust methods for such cases, but it is not immune to an omalous property predictions. The BLYP and BPW91 functionals fail dramatica lly for rectangular O-4(+) and F-4(+), where they are unable to find a boun d minimum. (C) 2001 American Institute of Physics.