Structural study of Rb and Cl coadsorption on Cu(111): a case of overlayer compound formation

Abstract

A structural study of the adsorption of Rb on a Cu(111)( √ 3 × √ 3)R30 • -Cl surface has been conducted using normal-incidence x-ray standing-wavefield absorption at both the Cl and Rb surface atoms. The results indicate reaction of the coadsorbates to form an overlayer of approximately 1.2 ML of RbCl(100) which is essentially incommensurate with the substrate. The RbCl-Cu outermost layer spacing is similar to that seen for pure Rb adsorption on Cu(111). This RbCl layer is spread over the surface and not agglomerated into thicker islands. The results are consistent with prior characterization of the system by Auger electron spectroscopy and temperature-programmed desorption, and with STM studies of NaCl deposition on Al(111).

Surface structure determination using x-ray standing waves

“…Thus, atomic O has been investigated on Al (111) [25] and Cu (111) [214], and S has been studied on Cu (111) [215][216][217], Ni (111) [218][219][220], Pd (111) [221], Rh (110) [222] and Rh (111) [223]. Several halogen adsorption phases have also been investigated, notably Cl on Cu (111) [21,22], Ni (100) [224,225], Ni (111) [226][227][228] and Rh (111) [229], Cl + Br coadsorption [230] and Cl + Rb coadsorption [231] on Cu (111), and I adsorption on Pd (111) [232] and Rh (111) [229]. Finally, there has been one investigation of adsorbed P on Rh (111) [233,234].…”

SODIUM AND CHLORINE COADSORPTION ON Si(100)

“…Analogous behavior has been observed during Rb and Cl interaction on Cu(111) surfaces where they form RbCl grown in the (100) direction. 44 In that case the dimensions of the Rb and Cl ions compel part of RbCl to form a second layer.…”