Gj. Jackson et al., The structure of the Cu(111)(root 7 x root 7)R19 degrees-S surface phase: a new normal-incidence X-ray standing wave study, SURF SCI, 453(1-3), 2000, pp. 183-190
The local geometry of the adsorbed sulphur atoms in the Cu(111)(root 7 x ro
ot 7)R19 degrees-S surface phase has been investigated with normal-incidenc
e X-ray standing wavefield (NIXSW) absorption using the (111), ((1) over ba
r 11) and (200) Bragg reflections. The results are compared with the predic
tions for previously proposed models based on earlier investigations using
NIXSW [but only the (111) reflection], surface extended X-ray absorption fi
ne structure, quantitative low energy electron diffraction, surface X-ray d
iffraction (SXRD) and scanning tunneling microscopy. The best agreement is
found for the model deduced from SXRD based on Cu4S adclusters, but for the
specific overlayer substrate registry in which these clusters are centred
atop an outermost substrate layer Cu atom. All of the other models show sig
nificant inconsistencies with these new data. (C) 2000 Elsevier Science B.V
. All rights reserved.