Assessment of density functional theory for the prediction of the nature of the oxirene stationary point

Abstract

The nature of the stationary point of oxirene, cyclic C 2H 2O, has been examined using selected GGA and hybrid functionals in combination with a number of basis sets. All GGA functionals (BLYP, BP91, PBE, HCTH, HCTH147, and HCTH407) predict the stationary point to be a transition state and show very little basis set dependence. The hybrid functionals (B3LYP, B3P91, PBE0, B97, B97-1, and B3P86), on the other hand, show more basis set dependence and predict oxirene to be a minimum in a number of cases. However, these parameterized hybrid functionals are not consistent in their characterization of oxirene. The theoretically derived hybrid functional PBE0 predicts oxirene to be a minimum with 11 of the 12 basis sets used and results with the largest basis set are in good agreement with earlier predictions with the high level correlated method, CCSD(T).