Ab Initio Molecular-Dynamics Simulations of Adsorption of Dye Molecules at Surfaces

We present results of ab initio total energy calculations and molecular-dynamics simulations of dye molecules on the NaCl(100) surface. The investigations concentrate on the flat dye molecules trimethin, [C₁₉H₁₇N₂O₂]⁺, which form sandwich-like structures if closely packed, and the cyanine molecule monomethin, [C₂₁H₂₃N₂]⁺, which shows a typical stereochemical deformation due to two repulsive methyl groups. The molecular-dynamics simulations are able to reproduce the experimentally observed configurations of the charged dye molecules on surfaces.