Photoelectron Diffraction from Ni(001)c(2 ×2)-S(2p)

Polar-angle-dependent photoelectron diffraction (PPD) of the S 2p core photoemission from Ni(001)c(2 ×2)-S has been measured by using synchrotron radiation at photon energies of 228 and 250 eV and along the [10] and [11] azimuths. The diffraction pattern has been calculated with a single scattering cluster model. A simple equation for photoelectron diffraction using the atomic scattering factor for a spherical incident wave has been derived for the calculation. The calculated PPD pattern using structure parameters obtained by LEED has been in good agreement with the observed PPD data.