TRIAZENE PROTON AFFINITIES - A COMPARISON BETWEEN DENSITY-FUNCTIONAL, HARTREE-FOCK, AND POST-HARTREE-FOCK METHODS

The consistency of three density functional computational implementations (DMol, DGauss, and deMon) are compared with high-level Hartree-Fock and Moller-Plesset (MP) calculations for triazene (HN=NNH2) and formyl triazene (HN=NNHCOH). Proton affinities on all electronegative sites are investigated as well as the geometries of the neutral and protonated species. Density functional calculations employing the nonlocal gradient corrections show agreement with MP calculations for both proton affinities and geometries of neutral and protonated triazenes. Local spin density approximation DMol calculations using numerical basis sets must employ an extended basis to agree with other density functional codes using analytic Gaussian basis sets. The lowest energy conformation of triazene was found to be nonplanar; however, the degree of nonplanarity, as well as some bond lengths, is dependent on the basis set, electron correlation treatment, and methods used for the calculation. (C) 1994 by John Wiley and Sons, Inc.