Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (09): 1907-1915.doi: 10.3866/PKU.WHXB201307022


Density Functional Theory Study on the Adsorption of Dodecylthiol on Au(111) Surface

FAN Xiao-Li, RAN Run-Xin, ZHANG Chao, YANG Yong-Liang   

  1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, P. R. China
  • Received:2013-05-06 Revised:2013-07-01 Published:2013-08-28
  • Contact: FAN Xiao-Li
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20903075, 21273172) and Program of Introducing Talents of Discipline to Universities, China (111 Project) (B08040).


By applying the first-principles methods based on density functional theory and the slab model, we have studied the non-dissociative and dissociated adsorptions of a dodecylthiol (C12H25SH) molecule on Au(111) surface. Based on the calculated results, the fate of the H atom has been analyzed, and the longchain adsorption and short-chain adsorption have been compared. We have performed structure optimizations for a series of initial structures with the S atom located on different sites with different tilt angles. This structure optimizations gave two surface structures before and after the dissociation of S―H; the standing-up and lying-down adsorption structures. Our calculations indicate that the C12H25SH molecule prefers to stay on the top site, the corresponding adsorption energies are 0.35-0.38 eV. The dissociated C12H25S group prefers to adsorb on the bri-fcc site, with adsorption energies of 2.01-2.09 eV. We have compared the non-dissociative C12H25SH/Au(111) and dissociated C12H25S/Au(111) with the H atom adsorbing onto Au and desorbing as H2, and found that the non-dissociative adsorption is more stable. The formation energy and the electronic structure showed that the non-dissociative adsorption belongs to the weak chemisorption, whereas the interaction between the S atom and Au surface becomes much stronger following cleavage of the S―H. A comparison of the adsorption of long-chain thiols on Au(111) surface with that of the short-chain thiols, indicates that the adsorption energies of the long-chain thiols are slightly larger, and the distances between the S atomand the surface Au atoms are slightly shorter.

Key words: Density functional theory, Dodecylthiol, Au(111) surface, Adsorption structure, Lying-down configuration, Electronic structure


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