Implementation and validation of DFT-D for molecular vibrations and dynamics: The benzene dimer as a case study

Semi-empirical correction to density functional theory for dispersion (DFT-D) has been implemented for energies, analytical gradients, and Hessians in order to explore potential energy surfaces by means of a complete set of first-principle methods. The impact of nonbonding interactions on structures, binding energies and zero-point energy contributions as well as on ab initio molecular dynamics trajectories have been investigated for the well known case of benzene dimer. While the static results are in remarkable agreement with the most sophisticated post-Hartree-Fock approaches, the low cost of DFT-D allows to unravel dynamical aspects too, which are mandatory for situations ruled by weak interactions.