TY - JOUR
T1 - Determination of the K adsorption site on Fe(110) with XSW
AU - Moest, B.
AU - Schmidt, T.
AU - Ceelen, W.C.A.N.
AU - Denier van der Gon, A.W.
AU - Falta, J.
AU - Brongersma, H.H.
PY - 2002
Y1 - 2002
N2 - We have used X-ray standing waves (XSW) in near normal incidence to determine the K–Fe bond length and the adsorption site of K at the saturation coverage at room temperature on the Fe(1 1 0) surface. Three different scattering geometries were used to enable the determination of the adsorption site by triangulation. From the results we conclude that the potassium atoms adsorb in a distorted hexagonal overlayer. The Fe–K distance, as determined from the measurements in the (2 2 0) Bragg reflection, is 3.4±0.2 Å. The long bridge site seems to be the preferred adsorption site for the potassium atoms in the distorted hexagonal overlayer. This geometry not only fits all the XSW data, but also explains all spots in the LEED pattern without the need to introduce multiple scattering. Comparison of the measured and simulated XSW data, based on the distorted hexagonal overlayer, enables a more accurate determination of the Fe–K bond length to 3.36±0.14 Å. This corresponds to a potassium hard sphere radius of rK=2.12±0.14 Å. This radius is among the largest reported for potassium on a metal, which is attributed to the high coverage and coordination of the K atoms in this overlayer arrangement.
AB - We have used X-ray standing waves (XSW) in near normal incidence to determine the K–Fe bond length and the adsorption site of K at the saturation coverage at room temperature on the Fe(1 1 0) surface. Three different scattering geometries were used to enable the determination of the adsorption site by triangulation. From the results we conclude that the potassium atoms adsorb in a distorted hexagonal overlayer. The Fe–K distance, as determined from the measurements in the (2 2 0) Bragg reflection, is 3.4±0.2 Å. The long bridge site seems to be the preferred adsorption site for the potassium atoms in the distorted hexagonal overlayer. This geometry not only fits all the XSW data, but also explains all spots in the LEED pattern without the need to introduce multiple scattering. Comparison of the measured and simulated XSW data, based on the distorted hexagonal overlayer, enables a more accurate determination of the Fe–K bond length to 3.36±0.14 Å. This corresponds to a potassium hard sphere radius of rK=2.12±0.14 Å. This radius is among the largest reported for potassium on a metal, which is attributed to the high coverage and coordination of the K atoms in this overlayer arrangement.
U2 - 10.1016/S0039-6028(02)02215-X
DO - 10.1016/S0039-6028(02)02215-X
M3 - Article
SN - 0039-6028
VL - 520
SP - 137
EP - 150
JO - Surface Science
JF - Surface Science
IS - 3
ER -