Distorted angular distribution of the 2p photoelectrons in argon

Two consecutive hemispherical electron energy analyzers have been used to measure the argon angular distribution of 2p photoelectron lines over two quadrants of the dipole plane. A significant anomaly in the intensity of the photolines is observed at several electron emission angles, suggesting asymmetry with respect to the electric field vector of synchrotron light. As a possible cause for the observed behavior, we consider an external field affecting the photoelectrons, and show that it is capable of breaking the left–right asymmetry of the angular distribution, giving rise qualitatively to the observed behavior. (paper)