Measurement of the equation of state and of the index of refraction of an amorphous glow discharge polymer up to 45 GPa

We present an experimental determination of the ambient temperature equation of state, P(ρ/ρ0,293 K), up to 45 GPa, of the glow discharge polymer (GDP) used as a confining capsule for the fusible deuterium-tritium mixture in inertial confinement fusion experiments. An original method has been implemented to measure both the compression factor and the refractive index versus pressure. The data are obtained in a diamond anvil cell with two sample chambers of equal thickness containing, respectively, the GDP and a NaCl reference. This experimental equation of state is compared to numerical first principles simulations. Deviations are ascribed to the difficulty to simulate the detailed atomic structure of the polymer under moderate pressure.