Cl electrosorption on Ag(100): Lateral interactions and electrosorption valency from comparison of Monte Carlo simulations with chronocoulometry experiments

We present Monte Carlo Simulations using an equilibrium lattice-gas model for the electrosorption of Cl on Ag(100) single-crystal surfaces. Fitting the simulated isotherms to chronocoulometry experiments, we extract parameters such as the electrosorption valency gamma and the next-nearest-neighbor lateral interaction energy phi_nnn. Both coverage-dependent and coverage independent gamma were previously studied assuming a constant phi_nnn [I. Abou Hamad, Th. Wandlowski, G. Brown, P.A. Rikvold, J. Electroanal. Chem. 554-555 (2003) 211]. Here, a self-consistent, entirely electrostatic picture of the lateral interactions with a coverage-dependent phi_nnn is developed, and a relationship between phi_nnn and gamma is investigated for Cl on Ag(100).Comment: Accepted for publication in Electrochimica Acta, 10 pages, 7 figures, 2 tables and an appendi

Electrosorption of Br and Cl on Ag(100): Experiments and Computer Simulations

We present chronocoulometry experiments and equilibrium Monte Carlo simulations for the electrosorption of Br and Cl on Ag(100) single-crystal electrode surfaces. Two different methods are used to calculate the long-range part of the adsorbate-adsorbate interactions. The first method is a truncated-sum approach, while the second is a mean-field-enhanced truncated-sum approach. To compare the two methods, the resulting isotherms are fit to experimental adsorption isotherms, assuming both a constant electrosorption valency &gamma and also a coverage-dependent &gamma. While a constant &gamma fits the Br/Ag(100) well, a coverage-dependent or potential-dependent &gamma is needed for Cl/Ag(100)

Ab initio calculations for bromine adlayers on the Ag(100) and Au(100) surfaces: the c(2x2) structure

Ab initio total-energy density-functional methods with supercell models have been employed to calculate the c(2x2) structure of the Br-adsorbed Ag(100) and Au(100) surfaces. The atomic geometries of the surfaces and the preferred bonding sites of the bromine have been determined. The bonding character of bromine with the substrates has also been studied by analyzing the electronic density of states and the charge transfer. The calculations show that while the four-fold hollow-site configuration is more stable than the two-fold bridge-site topology on the Ag(100) surface, bromine prefers the bridge site on the Au(100) surface. The one-fold on-top configuration is the least stable configuration on both surfaces. It is also observed that the second layer of the Ag substrate undergoes a small buckling as a consequence of the adsorption of Br. Our results provide a theoretical explanation for the experimental observations that the adsorption of bromine on the Ag(100) and Au(100) surfaces results in different bonding configurations.Comment: 10 pages, 4 figure, 5 tables, Phys. Rev. B, in pres

Charge Transport with Single Molecules ? An Electrochemical Approach

Nagasaki Symposium on Nano-Dynamics 2008 (NSND2008) 平成20年1月29日(火)於長崎大学 Invited Lectur