Publications

Analysis of hydrogen adsorption and surface binding configuration on tungsten using direct recoil spectrometry

Kolasinski, Robert K.; Hammond, K.D.; Whaley, Josh A.; Buchenauer, D.A.; Wirth, B.D.

Abstract In this work, we apply low energy ion beam analysis to examine directly how the adsorbed hydrogen concentration and binding configuration on W(1 0 0) depend on temperature. We exposed the tungsten surface to fluxes of both atomic and molecular H and D. We then probed the H isotopes adsorbed along different crystal directions using 1-2 keV Ne⁺ ions. At saturation coverage, H occupies two-fold bridge sites on W(1 0 0) at 25°C. The H coverage dramatically changes the behavior of channeled ions, as does reconstruction of the surface W atoms. For the exposure conditions examined here, we find that surface sites remain populated with H until the surface temperature reaches 200°C. After this point, we observe H rapidly desorbing until only a residual concentration remains at 450°C. Development of an efficient atomistic model that accurately reproduces the experimental ion energy spectra and azimuthal variation of recoiled H is underway.