The Static Lattice Model of Hardy and Bullough Applied to the Noble Metals to Calculate Divacancy Interaction Energies and Relaxations

Abstract

The discrete lattice method of Hardy and Bullough (1967) and Bullough and Hardy (1968) is applied to the noble metals to obtain estimates of the relaxations around a vacancy and of the near neighbour divacancy interaction energy. Accuracy is improved on earlier work by use of a point-formula integration technique. It is found that the soft phonon spectrum of gold leads to large relaxations and a divacancy interaction energy which is about half the single vacancy formation energy. It is therefore concluded that the model is too simplistic to describe the single and divacancy situations in gold, and may also not be accurate for copper and silver, though for the lighter elements the results are better.