Can hybrid DFT methods correctly compute the potential energy surface formic acid dimerization and proton transfer in the formic acid dimer? A comparison of hybrid DFT computed values with experimental and G1, G2, and G2MP2 generated data

The geometries of formic acid, the formic acid dimer, and the transition state structure for proton transfer in the formic acid dimer were computed with ab initio (HF and MP2) and hybrid DFT methods (B3LYP, B3P86, and B3PW91). The energy profile for this transformation was computed using the previously listed methods, as well as the Gaussian (G1, G2, and G2MP2) ab initio computational approach. The generated geometries and energies were compared with experimental data and the apparent shortcomings of the hybrid DFT methods for computation of this and similar systems are discussed. (C) 1997 Elsevier Science B.V.