A van der Waals density functional study of adenine on graphene: single-molecular adsorption and overlayer binding.

Department of Microtechnology and Nanoscience, University of Technology, Göteborg, Sweden.
Journal of Physics Condensed Matter (Impact Factor: 2.22). 03/2011; 23(13):135001. DOI: 10.1088/0953-8984/23/13/135001
Source: PubMed

ABSTRACT The adsorption of an adenine molecule on graphene is studied using a first-principles van der Waals functional, vdW-DF (Dion et al 2004 Phys. Rev. Lett. 92 246401). The cohesive energy of an ordered adenine overlayer is also estimated. For the adsorption of a single molecule, we determine the optimal binding configuration and adsorption energy by translating and rotating the molecule. The adsorption energy for a single molecule of adenine is found to be 711 meV, which is close to the calculated adsorption energy of the similarly sized naphthalene. On the basis of the single-molecular binding configuration, we estimate the cohesive energy of a two-dimensional ordered overlayer. We find a significantly stronger binding energy for the ordered overlayer than for single-molecule adsorption.

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