The dielectric function of mica and quartz determined by electron energy losses

Electron energy loss measurements have been made up to 40 eV on specimens of several members of the mica group and quartz. By means of a Kramers-Kronig analysis the dielectric functions epsilon 1 and epsilon 2 have been deduced from the energy loss function. The excitations observed in mica and quartz are discussed with respect to the basic crystal structure (SiO 4 tetrahedra) of both materials.