title: Validation of the density-functional based tight-binding approximation method for the calculation of reaction energies and other data.
abstract: We investigated the performance of the approximative density functional method DFTB versus BLYP and G2 with respect to zero-point corrected reaction energies, vibrational frequencies, and geometry parameters for a set of 28 reactions and 22 representative molecules containing C, H, N, and O (DFTB--density-functional based tight-binding approximation). The DFTB reaction energies show a mean absolute deviation versus the G2 reference of 4.3 kcalmol only. The corresponding value for the vibrational frequencies amounts to 75 cm(-1) versus BLYP/cc-pVTZ. With very few exceptions bond lengths and angles are in excellent agreement with the results of higher-level methods.
authors.affiliation: Theoretical Physics, Faculty of Science, University of Paderborn Warburger Strasse 100, Germany. t.krueger@phys.uni-paderborn.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Krüger
authors.forename: Marcus
authors.initials: M
authors.lastname: Elstner
authors.forename: Peter
authors.initials: P
authors.lastname: Schiffels
authors.forename: Thomas
authors.initials: T
authors.lastname: Frauenheim