Figure 1

Electron density differences between the surface and bulk layers of bare Au(111) projected on the $⟨111⟩$ surface. Filled black circles represent the Au atoms and the boundaries of the $1\times 1$ surface unit cell are indicated with dashed lines. Note that the density increases in the Au-Au bonds along $[\overline{2}11]$ and $[\overline{1}10]$ leading to the calculated tensile stress.Reuse & Permissions

Figure 2

(a) Structure of methylthiolate adsorbed on Au(111) (top view). The different kinds of Au atoms on this surface are shown by the letters T, B, F, and H for on-top, bridge, fcc, and hcp hollows, respectively. Arrows indicate the principal axes of the anisotropic surface stress tensor. ${\mathbf{v}}_1$ is along the $[01\overline{1}]$ direction parallel to a line of bridge atoms while ${\mathbf{v}}_2$ is along the tilt direction $[\overline{2}11]$ of the molecules. (b) Side view of the same system indicating isosurfaces of the charge-density difference upon adsorption. Charge is removed from the bond between the bridge Au atoms. Arrows indicate the displacements of the bridge Au atoms. (c) Stress anisotropy from a hexagonal lattice of tilted point dipoles. The signs in the circles in the top panel indicate attraction (−) or repulsion (+). The sign of the corresponding stress is opposite. The magnitude of the energy (force) is plotted as a function of the location of the neighbor in units where $\mu$, $R$, and $4\pi {ϵ}_0$ are 1. (d) Electron density difference arising in the $⟨111⟩$ surface plane upon methanethiolate adsorption. Depletion occurs between bridge atoms where the thiol binds. Black circles indicate the location of the Au atoms in the surface unit cell (dashed lines).Reuse & Permissions