Probing adsorption sites on thin oxide films by dynamic force microscopy

Site specific atomically resolved dynamic force spectroscopy measurements were performed on a thin MgO film grown on Ag(001). The microscope is operated in ultrahigh vacuum at low temperature to ensure defined imaging condition, high stability, and drift reduction. Atomically resolved dynamic force microscopy images have been combined with site specific frequency shift versus distance measurements. The frequency shift is measured as a function of z and the lateral displacement. With these measurement characteristics the authors are currently probing inequivalent surface sites on thin MgO films to extract atomic-scale information on surface chemical reactivity and possible adsorption sites for metal atoms and small clusters.