A valence band photoemission study of Pb adsorption on Rh(100) and Rh(110)

作者：Svec M; Dudr V; Sutara F; Tsud N; Skala T; Chab V; Matolin V; Prince K C^*

来源：Surface Science, 2007, 601(24): 5673-5677.

DOI：10.1016/j.susc.2007.06.042

• rhodium
• lead
• photoemission
• adsorption
• bimetallic surface alloys

We have studied the adsorption of Pb on the Rh(100) and (110) surfaces by photoemission and low energy electron diffraction (LEED), and tested the chemical properties by adsorption of CO. Pb forms two distinct c(2 x 2) phases on Rh(I 0 0), according to the temperature of the substrate. The phase formed below about 570-620 K, denoted alpha-c(2 x 2), reduces the coverage of adsorbed CO but does not affect the valence band spectrum of the molecule. The phase formed above this temperature, denoted beta-c(2 x 2), also reduces the coverage of adsorbed CO but the valence band spectrum of the adsorbed CO is strongly affected. The two phases are also characterised by a slightly different binding energy of the Pb 5d(5/2) level, 17.54 eV for the alpha phase and 17.70 for the beta phase. The Pb/Rh(110) surface shows two ordered Pb induced phases, c(2 x 2) and p(3 x 1). CO adsorbs on the first with reduced heat of adsorption and with a valence band spectrum that is strongly altered with respect to CO adsorbed on clean Rh(110), but does not adsorb on the p(3 x 1) structure at 300 K. We compare the present results with previous results from related systems.

• 出版日期2007-12-15