Kinetic energy dependence on initial sticking rate of O molecular beams on Ni(111) surface

Inoue, Keisuke*; Teraoka, Yuden; Kawakami, Yasunori*; Hiraya, Atsunari*

In this study, the oxidation states of Ni(111) surface, made by irradiation of a supersonic O molecular beam (SSOMB), were analyzed using synchrotron radiation photoemission spectroscopy (SR-XPS). The surface temperature was 300 K during both SSOMB irradiation and SR-XPS measurements. After irradiation of SSOMB on the Ni(111) surface to some extent, the evolution of the surface oxides were observed by core level photoemission spectra of Ni3p and O1s, and oxygen uptake curves were measured at every translational energy of O beam. The initial sticking rate increased with increasing translational energy from 0.5 eV to 1.0 eV, slightly decreased up to 2.2 eV, and a remarkable re-increase was observed in the region around 2.3 eV. These results imply that high speed O molecules adsorb by new adsorption mechanisms.