Initial sticking probability of O2 on Cu(410)

We present here a supersonic molecular beam investigation of the initial sticking probability (SO) for the O-2/Cu(410) system. Over the temperature range between 130 and 800 K adsorption occurs dissociatively and So increases up to similar to 0.7 with beam energy, indicating that the process is activated. So is larger for angles corresponding to molecules impinging on the step rises, implying that defects are more reactive than terrace atoms. The saturation value of S-0 is however lower than for the parent low Miller index surfaces; this indicates that the reactivity at nanosized terraces is reduced compared to extended Cu(100) faces. A precursor mediated adsorption path is observed at the lowest translational energy (E-i) below 150 K, as in the case of O-2/Cu(110) and at variance with O-2/Cu(100). At low T and higher energy and for all E-i at T > 150 K, adsorption occurs directly, yielding a sticking probability independent of surface temperature

Pressure and temperature dependence of cuprous oxide nucleation on Cu(410)

We studied the oxidation of Cu(410) during thermal O-2 exposure using high-resolution electron energy-loss spectroscopy. Cu2O is identified by loss peaks at 19 and 79 meV. By monitoring the intensity of the latter, we find that Cu2O formation depends strongly on the surface temperature and on the O-2 pressure and is kinetically limited by the impinging O-2 flux. Thermally activated step roughening, leading to detachment of Cu adatoms from the step edge, acts as a source of mobile Cu atoms, allowing for subsequent nucleation of Cu2O patches