REPULSIVE INTERATOMIC POTENTIALS CALCULATED USING HARTREE-FOCK AND DENSITY-FUNCTIONAL THEORY METHODS

The repulsive part of the interatomic potential affects the outcome of computer simulations of many irradiation processes of practical inter est, like sputtering and ion irradiation range distributions. The accu racy of repulsive potentials is studied by comparing potentials calcul ated using commonly available density-functional theory (DFT) and Hart ree-Fock (HF) methods to highly accurate fully numerical HF and Hartre e-Fock-Slater (HFS) calculations. We find that DFT calculations utiliz ing numerical basis sets and HF calculations using decontracted standa rd basis sets provide repulsive potentials which are significantly imp roved compared to the standard universal ZBL potential. The accuracy o f the calculated potentials is almost totally governed by the duality of the one-particle basis set. The use of reliable repulsive potential s open up new avenues for analysis of ion irradiation experiments. (C) 1997 Elsevier Science B.V.