Beyond RPA: dynamical exchange effects and the two-dimensional electron gas

Dynamic exchange interactions can be introduced in the dielectric function via a dynamic local field factor. We study the effects of this inclusion on the energy-loss function of a two-dimensional electron gas, using the dynamic local field factor that we derived recently via the dynamical exchange decoupling method. The results are compared with the dielectric function in the Random Phase Approximation, showing a drastic influence of the dynamic exchange interactions.