Optical Loss function vs energy-loss function?
Looking at an optical loss function generated via TDDFT, it seems to resemble a VEELS (valence electron energy-loss function) or low-loss EELS.
However, If I take the dielectric functions computed via BSE, and understand that the intensity of the valence electron energy loss spectrum is related to the dielectric function by
I=-img(1/(e)) Where e is the dielectric function, and perform the conversion, I get a completely different graph.
What am I missing here?