title: Elastic properties of the light actinides at high pressure.
abstract: Using density-functional perturbation theory, we have calculated the elastic constants for the ground-state crystal structures of the light actinide metals both at their equilibrium volumes (for Th through Np) and as a function of pressure (for Th through U). As necessary, we take into account the effects of atomic relaxation and show that these can be neglected for α-U, but are crucial for α-Np. The elastic constants of Th and U are compared with experimental measurements near ambient conditions and good agreement is found. Studies of the Born stability criteria in pressure reveal that Th and Pa are mechanically unstable while U remains stable up to 85 GPa, as is observed in diamond anvil cell experiments.
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France.
authors.forename: J
authors.initials: J
authors.lastname: Bouchet
authors.forename: R C
authors.initials: RC
authors.lastname: Albers