High-resolution x-ray-photoemission study of single crystallineSr2CuO2Cl2

${\mathrm{Sr}}_2{\mathrm{CuO}}_2{\mathrm{Cl}}_2$ contains ${\mathrm{CuO}}_2$ planes separated by ionic SrCl block layers and can be regarded as a model substance for cuprates concerning many of their physical properties, in particular the dynamics of valence-band holes in a two-dimensional antiferromagnetic background. We present and discuss core-level and valence-band photoemission data. The $\mathrm{C}\mathrm{u}-2p$ photoelectron spectrum differs from the spectra of other cuprate compounds, in particular with regard to the parent cuprates of the high-$T_c$ superconductors. The $\mathrm{C}\mathrm{u}-2p$ main lines are comprised of more than two peaks with strong satellite emission which exhibits a distinct angular-dependent fine structure. We present calculations of a ${\mathrm{Cu}}_5{\mathrm{O}}_{16}$ cluster within the $d-p$ model and discuss the features in the main line of the $\mathrm{C}\mathrm{u}-2p$ photoemission spectrum in terms of the different screening channels available in ${\mathrm{CuO}}_2$ planes.