TY  - JOUR
AU  - Al-Shakran, Mohammad
AU  - Kibler, Ludwig A.
AU  - Jacob, Timo
AU  - Ibach, Harald
AU  - Beltramo, Guillermo
AU  - Giesen, Margret
TI  - Repulsive interactions induced by specific adsorption: Anomalous step diffusivity and inadequacy of nearest-neighbor Ising model
JO  - Surface science
VL  - 651
SN  - 0039-6028
CY  - Amsterdam
PB  - Elsevier
M1  - FZJ-2017-02398
SP  - 84 - 93
PY  - 2016
AB  - This is Part I of two closely related papers, where we show that the specific adsorption of anions leads to a failure of the nearest-neighbor Ising model to describe island perimeter curvatures on Au(100) electrodes in dilute KBr, HCl and H2SO4 electrolytes and the therewith derived step diffusivity vs. step orientation. This result has major consequences for theoretical studies aiming at the understanding of growth, diffusion and degradation phenomena. Part I focuses on the experimental data.As shown theoretically in detail in Part II (doi:10.1016/j.susc.2016.03.022), a set of nearest-neighbor and next-nearest-neighbor interaction energies (ϵNN, ϵNNN) can uniquely be derived from the diffusivity of steps along 〈100〉 and 〈110〉. We find strong repulsive next-nearest neighbor (NNN) interaction in KBr and HCl, whereas NNN interaction is negligibly for H2SO4. The NNN repulsive interaction energy ϵNNN therefore correlates positively with the Gibbs adsorption energy of the anions. We find furthermore that ϵNNN increases with increasing Br− and Cl− coverage.The results for ϵNN and ϵNNN are quantitatively consistent with the coverage dependence of the step line tension. We thereby establish a sound experimental base for theoretical studies on the energetics of steps in the presence of specific adsorption.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000379105500013
DO  - DOI:10.1016/j.susc.2016.03.021
UR  - https://juser.fz-juelich.de/record/828439
ER  -