Improved adsorbate fluctuation measurements and their explanation by different diffusion mechanisms: I. Arguments in favour of single adatoms surface diffusion

Abstract

Field emission fluctuations of the adsorption system W(112)/K. have been investigated by the cross-correlation technique using a field emission tube with a variable distance between the probed regions. At high temperatures the adsorbate behaviour can be described by the standard diffusion model. The results obtained were used to determine approximate diffusion parameters. The activation energy of surface diffusion of potassium along the 〈111〉 crystallographic direction on the W(112) plane is Q = 0.70±0.04 eV and the diffusion constant D 0 = 0.04±0.04 cm 2/ s.