Asymmetry of Compton profiles Original Research Article

The asymmetry and observed anomalous broadening of experimental Compton profiles measured at synchrotron radiation sources have raised questions on the validity of the impulse approximation and the strength of the electron–electron interaction in metals. However, asymmetry and broadening can also be introduced by experimental artifacts. In order to address these issues we have made a systematic study on simple systems using various incident photon energies and different spectrometers. In addition, we have performed simulations on the effect of dead time and an asymmetric instrument function in the measured Compton profiles. We conclude that the observed asymmetry of Compton profiles of Be and Na does not originate from any experimental artifacts, but is due to the failure of the impulse approximation. This is confirmed by quasi-self consistent field calculations of the core electron Compton profiles, which agree quite well with the experimental results.