Angular dependent resonant photoemission processes at the 2p thresholds   in nickel metal
  Angle-resolved valence-band resonant photoemission of nickel metal has been measured close to the 2p core-level thresholds with synchrotron radiation. The well-known 6-eV correlation satellite has an intensity enhancement of about two orders of magnitude at resonance. The angular dependence of the photoemission intensity has been studied as function of photon energy and provides unambiguous evidence for interference effects all the way up to the resonance maximum. The observation of different angular asymmetries, {\beta}, for the valence band and the satellite is discussed in connection to the origin of the resonant photoemission process and the character of the satellite. 
M. Magnuson, A. Nilsson, M. Weinelt and N. M{\aa}rtensson
cond-mat.mtrl-sci cond-mat.str-el physics.chem-ph