He scattering on a TiO2(1 1 0) surface

We present measurements of energy-losses and neutralisation of helium ions on a TiO₂(1 1 0) surface at low keV energies. Measurements were performed in the 1–4 keV energy range. The target azimuthal orientation dependence of total scattering intensity profiles, energy-losses and probability of electron capture or loss were determined. On the basis of Marlowe simulations it is concluded that ion scattering intensities give indications about defects regarding surface bridging O atoms. Variations in energy losses for different scattering directions are reported. Ion fraction measurements were made using both incident ions and neutrals. Similar ion fractions were found indicating that He is efficiently neutralised and ions result from reionisation. These ion fractions are found to depend on the azimuthal orientation and have a minimum along the main crystallographic directions.