Computer Simulation of Split Interstitial Equilibrium Positions and Binding Energies in a Tungsten Crystal.

Computer simulations were performed to locate the equilibrium positions and binding energies of interstitial He, Ne, Ar, Kr, and Xe in a tungsten crystal. Heavy interstitial atoms in tungsten share a lattice site with the atom that normally occupies that site and form what is called a split interstitial. Three characteristic interstitial sites were located relative to each lattice site tested. The distance of the impurity atom from the site was seen to vary roughly inversely with its mass, and the displacement of the lattice atom increased with the mass of the impurity atom. The foreign atom in its interstitial position was tested to determine the minimum initial kinetic energy needed to escape the lattice, as well as the optimum escape direction. (Author)