Interatomic potentials for hydrogen in α -iron based on density functional theory

We present two interatomic potentials for hydrogen in α -iron based on the embedded atom method potentials for iron developed by Mendelev [Philos. Mag. 83, 3977 (2003)] and Ackland [J. Phys.: Condens. Matter 16, S2629 (2004)]. Since these latter potentials are unique among existing iron potentials in their ability to produce the same core structure for screw dislocations as density functional theory (DFT) calculations, our interatomic potentials for hydrogen in iron also inherit this important feature. We use an extensive database of energies and atomic configurations from DFT calculations to fit the cross interaction of hydrogen with iron. Detailed tests on the dissolution and diffusion of hydrogen in bulk α -iron, as well as the binding of H to vacancies, free surfaces, and dislocations, indicate that our potentials are in excellent overall agreement with DFT calculations.