0000000000654915
AUTHOR
Kjeld O. Jensen
Noble-gas bubbles in metals: Molecular-dynamics simulations and positron states.
A theoretical treatment of atomic structure and positron states in noble-gas bubbles in metals is presented. The Al-He and Cu-Kr systems are considered as specific examples. For large bubbles (radii above a few tens of angstroms) a calculational scheme is developed combining molecular-dynamics results for the metal--noble-gas interface with positron calculations. It is demonstrated that a positron is trapped at the surface of a noble-gas bubble, i.e., at the metal-gas interface. The annihilation rate with metal electrons is similar to that at a clean surface, while simultaneously there is a significant annihilation rate with gas-atom electrons. This enables relationships between the gas den…
Helium bubbles in metals: Molecular-dynamics simulations and positron states.
By combining molecular-dynamics results for the aluminum-helium interface with positron-state calculations it is demonstrated that a positron is trapped at the surface of a He bubble in Al. The annihilation rate with Al electrons is similar to that at a clean surface, while simultaneously there is a significant annihilation rate with He electrons. This enables one to obtain a useful relation between the positron lifetime and helium densities in bubbles.