Electron Spin Resonance Investigations of the Molecular Motion of NO2 on Al2O3(111) under Ultrahigh Vacuum Conditions

Abstract

We report on the first observation of electron spin resonance spectra of submonolayer coverages of small adsorbates on an epitaxially grown single crystal ${\mathrm{Al}}_2$ ${\mathrm{O}}_3$ film under ultrahigh vacuum conditions. The spectra reveal a clear temperature and coverage dependence. The changes of linewidths and intensities as a function of surface temperature and coverage provide insight into diffusion processes on the ${\mathrm{Al}}_2$ ${\mathrm{O}}_3$ surface.