Typical sticking measurement performed in our helium atom scattering apparatus. Opening of the first flag let the beam enter the main chamber where the oxygen background partial pressure is measured by means of a quadrupole mass spectrometer. When the second flag is open, O2 molecules strike the crystal surface and stick on it, thus causing a decrease in the background partial pressure (see text). In this measurement, the incident angle is fixed at Θ i = 15°, beam energy is at 200 meV, and the surface temperature is 100 K.
Intensity of the specularly reflected He beam during Cu evaporation on Ru(0001) versus time. The evaporation rate is about 0.1 ML/min. The two maxima in the spectrum correspond to the completion of the first and second Cu layers, respectively.
Initial sticking probability of O2 molecules versus incident normal energy for the clean Ru(0001) surface, 1 ML Cu, and 2 ML Cu evaporated on it, and Cu(111). The crystal temperature is 300 K, and the angle of incidence is Θ i = 15°. The data reported by Wheeler et al. 30 for Ru(0001) under similar incident conditions are also shown.
Intensity of the specularly reflected H2 molecules versus time for the clean Ru(0001) surface and 1-2 ML Cu/Ru(0001). For the Cu surfaces, H2 sticking is estimated to be reduced by a factor 103 compared to the clean Ru(0001) surface.
Intensity of the specularly reflected He beam as a function of time while dosing D2O with the beam, for the clean Ru(0001) surface, 2 ML Cu/Ru(0001), and Cu(111). The energy of the D2O molecules is estimated to be 250 meV. Surface temperature is 100 K, and the angle of incidence is Θ i = 15°.
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