A High Pressure Distorted a-Uranium (Pnma) Structure in Plutonium

摘要

Under pressure many rare earths and actinide metals transform to a-Ustructure or its lower symmetry distorted forms. We have reinterpreted thediffraction data of Dabos et al for Pu (reference 4) and find that a Am IV typedistorted a-U structure in Pnma space group can explain this for its highpressure phase. The structures of this phase and a-Pu are both shown to have adistorted hcp topology. The upturn in the atomic volume of Pu at 0.1 MPa canalso be rationalized on the basis of this proposal