New method to determine the dielectric constants of acceptor type GIC

The usual way to determine the dielectric constants is to measure the reflectivity at normal incidence in a large energy range to perform than a Kramers-Kronig analysis. We present a novel method based on a reflectivity measurement at fixed energy in a Fresnel configuration. The reflectivity is measured as a function of angle and polarization in the infrared region. We can simultaneously determine the value of the dielectric constants parallel and perpendicular to the graphitic planes. This method allows for in-situ intercalation and studies of the intercalation kinetics. The first results for AsF₅ stage 1 intercalated graphite are reported and discussed in the framework of the 2D-Blinowski-Rigaux model.