Modeling Sn scattering through hydrogen using DFT potentials

A novel method of modeling Sn (tin) scattering through H2 (molecular hydrogen) is examined. Density-functional theory (DFT) software from the Amsterdam Modeling Suite was used to determine the interaction energy of Sn and H2 at varying spacing and orientations. This data was used to generate a function that describes the average interaction energy with respect to distance between the two species for neutral Sn as well as selected Sn ionized states. These resulting functions were inserted into RustBCA, a binary collision approximation code for ion-material interactions. The scattering of a Sn beam through H2 was modeled for each newly generated potential, along with well-known potentials such as ZBL and Moliere for comparison. Legacy software, such as TRIM, is not capable of modeling scattering using potentials that contain attractive components. The potentials generated with DFT have attractive components, so this analysis is only possible now using RustBCA. This method can give more accurate results than previous work. A model using the ZBL potential wherein a neutral Sn beam of 10 keV scattered through 15 cm of H2 left 87.8% of the Sn atoms within 41.4 millisteradians of the primary axis and an average energy of 816.3 eV ± 8.71 eV. The same model with a DFT-generated potential gives a much narrower particle distribution with higher average energies. This modeling work will also be compared against ongoing experimental measurements of Sn ions through H2 for further comparison.