On the performance of local density approximation in describing the adsorption of electron donating/accepting molecules on graphene

In order to asses performance of the LDA in describing physisorption on graphene, adsorptions of TCNE, TCNQ, TNF, TTF, and DMPD as well as four benzene derivatives on C54H18 and C110H30 were explored with a variety of DFTs such as MPWB1K, M06-2X, PBE-D and LSDA. Although it is well known that the LDA considerably overestimate non-covalent interaction, the LSDA predicted adsorption energies except for TCNE on C110H30 are systematically lower than those from the M06-2X by 0.4-3.2 kcal/mol, and they are more significantly lower than those from the PBE-D for all the molecules by 3-6 kcal/mol. However, the LSDA adsorption energy sequence is consistent with that from the PBE-D, TNF similar to TCNQ > TCNE similar to DMPD > TTF. Moreover, the domain interaction between the electron donor and acceptor molecules with graphene through cooperative pi center dot center dot center dot pi, C-H center dot center dot center dot pi and N-H center dot center dot center dot pi were visualized with sign(lambda(2)) x rho, and the relationships between the binding energy with London force, molecular electronegativity, and frontier orbital level were extensively discussed. (C) 2012 Elsevier B. V. All rights reserved.