The use of a pair potential for the study of defects and disorder in aluminum

The authors have examined the usefulness of the Dagens, Rasolt and Taylor (DRT) interionic potential (1975) for calculating disorder and defect properties in Al from the point of view of a molecular dynamics (MD) computer simulation. The problem was complicated by the strong long-range oscillations present in the Al potential and careful attention was paid to this detail. The authors confirmed that the low-temperature phonons generated by the MD program agreed very well with the quasi-harmonic phonons of DRT and then proceeded to generate the high-temperature phonons. They also calculated the liquid structure factor obtaining satisfactory agreement with experiment. They found, not too surprisingly, that the calculated vacancy formation energy for Al was much smaller than experiment by about 0.5 eV. However they noted that if one allows for re-screening effects in the vicinity of the vacancy a subtle three-body force comes into play which, on a crude argument, accounts for this difference