Atomistic simulation of point defects behavior in ceria

摘要

The cerium and oxygen threshold displacement energies and the Frenkel pair recombination in CeO_2 have been investigated with empirical potential molecular dynamics simulations. The oxygen and cerium threshold displacement energies have been evaluated to be 27 and 56 eV, respectively, in agreement with experimental results. The short-range cerium and oxygen Frenkel pair recombination processes are found to be strongly dependent on the local topology and the pathways. The oxygen Frenkel pair recombinations are either spontaneous or thermally activated unlike the standard recombination usually defined in rate equations. The lifetime of Frenkel pair recombination is in general found to be much shorter than the characteristic time for single defect diffusion.