X-ray photoelectron diffraction at high angular resolution

We present x-ray photoelectron diffraction (XPD) measurements at an angular resolution of {~}±{}1.0^∘{} which is much higher than in any prior study. Emission from the Ni 2p3/2 core level of Ni(001) under Al K{α} excitation is considered. The azimuthal XPD patterns are found to exhibit considerable fine structure not observed previously, including peaks whose full widths at half-maximum intensity are only a few degrees. The experimental data are found to be well described by single-scattering-cluster calculations with spherical-wave scattering. Fine structure due to Bragg-like scattering (Kikuchi bands) is also observed in both experiment and theory.