Evaluation of first-principles techniques for obtaining materials parameters of α-uranium and the (001)α-uranium surface

First- principles calculations based on the projector augmented- wave ( PAW ) technique have been applied to the prediction of materials properties of alpha-uranium and its ( 001 ) surface. The results of the PAW calculations are shown to be comparable in accuracy to the full- potential calculations reported elsewhere. In addition to calculating lattice constants and elastic moduli, the vacancy formation energy ( 1.95 eV ), ( 001 ) surface relaxation (- 3.5% for delta(12) and + 1.2% for delta(23) ), (001) surface energy (1.4 J/m(2)), and (001) work function ( 3.6 eV ) were also obtained. The overall agreement with experiment is satisfactory. Using an elastic model for brittle-crack failure, a yield stress of 430 MPa was estimated. Further exploration of materials failure modes ( such as plastic deformation ) awaits a larger- scale atomistic treatment. Full spin- orbit and scalar relativistic calculations were shown to give results with similar levels of accuracy compared to experiment.