Ion-induced adsorption of oxygen at a Cu(110) surface

A preliminary report is given on experiments concerning the ion-induced adsorption of oxygen on copper. A strong enhancement of the sticking probability of oxygen is found during bombardment of the surface with neon ions in the keV region. The increase in the sticking probability is proportional to the primary ion intensities, used in this work (0.25–10 μA/ cm2)

Investigation of oxygen adsorption on Cu(110) by low-energy ion bombardment

The interaction of molecular oxygen with a Cu(110) surface is investigated by means of low energy ion scattering (LEIS) and secondary ion emission. The position of chemisorbed oxygen relative to the matrix atoms of the Cu(110) surface could be determined using a shadow cone model, from measurements of Ne+ ions scattered by adsorbed oxygen atoms. The adsorbed oxygen atoms are situated 0.6 ± 0.1 Å below the midpoint between two adjacent atoms in a 100 surface row. The results of the measurements of the ion impact desorption of adsorbed oxygen suggest a dominating contribution of sputtering processes. Ion focussing effects also contributes to the oxygen desorption. The ion induced and the spontaneous oxygen adsorption processes are studied using different experimental methods. Sticking probability values obtained during ion bombardment show a strong increase due to the ion bombardment

The influence of low energy ion beams on an adsorbing surface

Strong enhancement of the oxygen-chemisorption at a Cu(110) surface is measured during low energy (some keV) noble gas (Ne+) ion bombardment. This phenomenon is independent of the coverage and is linearly related to the number of impinging ions per second. A model description of the oxygen adsorption on a Cu(110) surface is given: the model of dissociative adsorption via a mobile precursor state is extended to take into account the twofold symmetry of the surface. From a comparison of model calculations with the experimental results, model parameters can be estimated. The estimated parameters are in agreement with the adsorbate-structure deduced from LEED patterns. Ion-induced adsorption is discussed with the aid of this model

Multiple scattering and neutralization aspects of low energy noble gas ions incident on a Cu (110) crystal

Experiments have been done with 1 keV Ne+ ions bombarding a Cu (110) single crystal in a (111) plane. From the measured energy spectra of the scattered ions the minimum and maximum scattering angles for multiple scattering on the surface are determined. These minimum and maximum scattering angles were also calculated using a computer model. The parameters for an interatomic potential function between ion and metal atom are determined by comparison of the experimental and calculated scattering angles. A neutralization model for an energetic ion at an atomic surface is given. The reliability of this model is tested by comparison of the results of computer calculations and the measured peak intensity distributions as a function of the scattering angle