| AVS 58th Annual International Symposium and Exhibition | |
| Surface Science Division | Tuesday Sessions |
| Session SS2-TuM |
| Session: | Self Assembled Monolayers and Networks |
| Presenter: | Duy Le, University of Central Florida |
| Authors: | D. Le, University of Central Florida M. Aminpour, University of Central Florida A. Kiejna, University of Wroclaw, Poland T.S. Rahman, University of Central Florida |
| Correspondent: | Click to Email |
The physisorption of 1,4 diaminebenzene (BDA) molecule on Au(111) surface is studied within the generalized gradient approximation of the density functional theory with the PBE [1], vdW-DF [2], and vdW‑DF2 [3] exchange correlation functionals. The binding energy of an isolated BDA adsorbed on Au(111) surface calculated from vdW-DF (vdW‑DF2) is 0.78 eV (0.84 eV) in better agreement with the experimental value (1.0 eV) [4] than that from PBE (0.37 eV), while the alignment of the molecule along the surface obtained from PBE (20o) is closer to the experimental value of 24o [4] than that of about 5o derived from vdW-DF (or vdW‑DF2). On the other hand, when interactions between the BDA molecules is included in the calculations, as would be the case if the molecules were to self-assemble, say in the form of a linear line structure on Au(111), inclusion of vdW interactions gives excellent agreement with experimental observations. In particular vdW‑DF and vdW‑DF2 predict the BDA tilt angles to be 23o and 21o, respectively. The binding energy of a BDA on Au(111) in this case is 0.70 eV and 0.71 eV, respectively. As is to be expected, PBE does not account for intermolecular interactions and does not give good agreement with the data. We suggest the presence of such alignment of molecules along the surface in the experiments, and that they are governed by hydrogen bonding between N and H atoms of neighboring BDA molecules. We compare our results also with unpublished STM data for the system.
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[2] M. Dion, H. Rydberg, E. Schröder, D. C. Langreth, and B. I. Lundqvist,Phys. Rev. Lett. 92, 246401 (2004)
[3] K. Lee, É. D. Murray, L. Kong, B. I. Lundqvist, and D. C. Langreth,Rev. B82, 081101 (2010).
[4] M. Dell’Angela , G. Kladnik, A. Cossaro, A. Verdini, M. Kamenetska, I. Tamblyn, S. Y. Quek, J. B. Neaton, D. Cvetko, A. Morgante, and L. Venkataraman, Nano Lett. 10, 2470–2474 (2010)
*Work supported by DOE Grant DE-FG02-07ER15842.