Tuning Charge Transfer in Ion–Surface Collisions at Hyperthermal Energies |
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| Authors: | Dr Yunxi Yao Prof Konstantinos P Giapis |
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| Affiliation: | Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA |
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| Abstract: | Charge exchange in ion–surface collisions may be influenced by surface adsorbates to alter the charge state of the scattered projectiles. We show here that the positive‐ion yield, observed during ion scattering on metal surfaces at low incident energies, is greatly enhanced by adsorbing electronegative species onto the surface. Specifically, when beams of N+ and O+ ions are scattered off of clean Au surfaces at hyperthermal energies, no positive ions are observed exiting. Partial adsorption of F atoms on the Au surface, however, leads to the appearance of positively charged primary ions scattering off of Au, a direct result of the increase in the Au work function. The inelastic energy losses for positive‐ion exits are slightly larger than the corresponding ionization energies of the respective N and O atoms, which suggest that the detected positive ions are formed by surface reionization during the hard collision event. |
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| Keywords: | gold ion exchange low-energy ion scattering reionization surface dynamics work function |
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