Temperature dependence of azimuthal X-ray Photoelectron Diffraction (XPD) from [formula omitted] core level of Cu(001): Experiment and single scattering cluster calculations

Abstract

The temperature dependence of X-ray photoelectron diffraction (XPD) affects in azimuthal distributions of Cu2p 3 2 core level intensities from a clean copper (001) single crystal has been measured in the range from ambient to 1010 K and for polar angles of emission relative to the surface of θ = 7° (corresponding to very high surface sensitivity) and θ = 45°. The XPD anisotropy Δ I/ I max at θ = 7° shows a decrease of 42.5% between ambient temperature and 1010 K while that for θ = 45° shows a 22.7% decrease over the same temperature range. Single scattering cluster calculations including Debye-Waller factors very well predict the variation of anisotropy with temperature at θ = 7°, while at θ = 45° theory significantly underestimates the decrease in Δ I/ I max, probably due to multiple scattering effects. The effective surface Debye temperature of 202 K deduced from theory and experiment for θ = 7° agrees well with prior determinations. The 7° XPD data give no evidence for surface melting effects on Cu(001) at temperatures up to T/ T melting = 0.74.