Structural investigation of monolayers prepared by deposition of (CH3S)(2) on the (111) face of single-crystal gold

2002-11-14
Danışman, Mehmet Fatih
Casalis, L
Bracco, G
Scoles, G
Although self-assembled monolayers made of long chains of n-alkanethiols [CH3(CH2)(n-1)SH] on Au(111) have been extensively studied in the past, the driving forces behind the appearance of the (3 x 2root3) superlattice observed at full coverage are still not completely understood. To focus on the role played by the sulfur headgroup minimizing the interactions between chains and to prevent a possible X-ray-induced damage, we have carried out a He atom diffraction study of the adsorption of the shortest (n = 1) thiol radical, obtained by dissociative adsorption of (CH3S)(2), on the Au(111) surface. Contrary to current literature reports, domains of the hexagonal (root3 x root3)R30degrees structure are observed to convert into the well-ordered (3 x 2root3) superstructure after annealing times of a few hours. The observation of peaks forbidden by the (3 x 2root3) model proposed by Fenter et al. (Fenter, P.; Eberhardt, A.; Eisenberger, P. Science 1994, 266, 1216) suggests a distortion of the symmetry, of the unit cell. The observed chemisorption and physisorption energies were in good agreement with the literature.

Citation Formats
M. F. Danışman, L. Casalis, G. Bracco, and G. Scoles, “Structural investigation of monolayers prepared by deposition of (CH3S)(2) on the (111) face of single-crystal gold,” JOURNAL OF PHYSICAL CHEMISTRY B, vol. 106, no. 45, pp. 11771–11777, 2002, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/42465.