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 C(54)H(18) and C(110)H(30) 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 C(110)H(30) 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~TCNQ>TCNE~DMPD>TTF. Moreover, the domain interaction between the electron donor and acceptor molecules with graphene through cooperative π···π, C-H···π and N-H···π were visualized with sign(λ(2))×ρ, and the relationships between the binding energy with London force, molecular electronegativity, and frontier orbital level were extensively discussed.