Simple Molecular Systems at Very High Pressures : computer simulation studies

We discuss the application of ab initio molecular dynamics simulations results to a variety of simple molecular systems under pressure. In particular we consider the polymerization and subsequent amorphization of C2H2 crystals upon compression up to 50 GPa, the determination of the ground state structure of the broken symmetry phase of H2 in the pressure range 100-150 GPa, the fate of methane and ammonia along the isentrope of the middle ice layers of Neptune. We also discuss preliminary applications to O2 and CO.