The question of the appropriate self-energy to be used in EXAFS and XANES seems overdue for improvements on the conventional Hedin-Lundqvist plasmon-pole approximation. Within Hedin's GW approximation the self energy Sigma(E) is determined by poles in G and poles in W = epsilon**(-1) V_coul. The electron gas plasmon-pole approximation was derived for 3d metals, and is questionable in insulators and other systems such as small particles. Indeed, the GW PP often overestimates loss. Efforts to improve on this are in progress, however, e.g., using ab initio calculations of epsilon**(-1). See for example, ``Electron self-energy calculation using a general multi-pole approximation," J. A. Soininen, J. J. Rehr and E. L. Shirley, J. Phys.: Condens. Matter, {\bf 15}, 2572 (2003). In the meantime, the self-energy can be adjusted in fits, e.g. to the mean free path. I'd be interested in hearing experimental evidence for the need for such corrections. J. Rehr