Sammendrag
The Embedded Atom Model (EAM) is applied to the study of vacancy form ation in bulk aluminium and lithium. Using the unrelaxed vacancy form ation energy determined from ab initio density functional calculation s as an "empirical" input parameter to the EAM procedure, the relaxat ion energy and formation volume are calculated. Structural relaxation around the vacancy is also investigated. In the case of aluminium, a t most a fifth nearest neighbour model is required and for lithium at least a ninth nearest neighbour model. We find that for aluminium, t he vacancy relaxation energy and formation volume is not a sensitive function of the unrelaxed vacancy formation energy giving values, whi ch agree well with both experiment and ab initio results. For Lithium the situation is somewhat different. Both the vacancy relaxation ene rgy and formation volume are found to be a noticeable function of the unrelaxed vacancy formation energy, the former being consistently hi gher than those of ab initio calculations. Nevertheless the correspon ding relaxed vacancy formation energies are found to agree well with the range of values determined by experiment. For both solids, struct ural relaxation was found to be insensitive to the unrelaxed vacancy formation energy, agreeing well with previous theoretical calculation s.
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