Spectrometer for the study of angle- and energy-resolved reactive ion scattering at surfaces

We describe an ion-surface scattering apparatus newly developed to investig ate the reactive scattering process of low-energy alkali-metal ions at surf aces. The apparatus consists of an alkali-metal ion gun that is rotatable b y 360 degrees, a quadrupole mass spectrometer QMS) with an ion energy analy zer, a sample manipulator with a heating-and-cooling stage, and an ultrahig h vacuum (UHV) chamber that houses these components. Preliminary experiment al results obtained from the apparatus are presented on angular and energy distributions of the ions scattered from clean Pt(111) and water-adsorbed P t surfaces.