It is common knowledge that following the absorption edge, where the photon energy equals the binding energy of a core electron, monotonic decrease in the absorption coefficient with increasing photon energy is observed (for example). Obviously it is so common, that everyone mentions it, but nobody cares to explain.

As I understand, in EXAFS case core electron is excited to the conduction band and photon with higher energy should just excite it to the higher energy level in conduction band. So why absorbtion decreases?