Experimentally determined interatomic potentials in low-energy atomic collisions relevant for nuclear fusion

Interatomic potentials were measured for combinations of chemical elements relevant for nuclear fusion. Angular scans of the scattering yield were performed on a W(110) and a Fe(100) single crystal using <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mi mathvariant="normal">H</a:mi><a:msup><a:mrow><a:mi mathvariant="normal">e</a:mi></a:mrow><a:mo>+</a:mo></a:msup></a:mrow></a:math> and <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"><d:msup><d:mrow><d:msub><d:mi mathvariant="normal">D</d:mi><d:mn>2</d:mn></d:msub></d:mrow><d:mo>+</d:mo></d:msup></d:math> beams with energies of 3 keV/atom using a time-of-flight low-energy ion scattering setup. Information on the interatomic potentials was deduced by reproducing width and intensity of minima and maxima in the angular scans in molecular dynamics simulations by adjusting the assumed screening length with a correction factor. Results from experiments were compared to common interatomic potential models and density functional theory predictions. Our measurements show that the uncorrected Thomas-Fermi-Molière and the Ziegler-Biersack-Littmark potentials overestimate the interatomic potential for the studied combinations. In contrast, the Yamamura-Takeuchi-Kawamura potential yields values slightly below our experimental result. At the same time, density functional theory predictions agree well with our experimental results for the He cases while differing significantly for the D cases.