Sur la constante dielectrique du graphite dans l'ultraviolet

Applying the Lorentz classical theory with 2 types of electrons (π and σ), the author finds the analytical behaviour of ∊(ω) in graphite (3-30eV energy range) when E is perpendicular to ' C' axis. Agreement between this rough theory and experiments is very good. Starting from this point of view, phenomenological explanations of electron energy losses anisotropy and dielectric constant in this frequency range can be made.