The adsorption of SiO molecules on MgO Surfaces as a model for the silicon lever atomic force microscope (AFM)

Computer simulation of a 1 :4 SiO monolayer adsorbed on a MgO monatomic slab has been performed by using the CRYSTAL "ab initio" program. The Mg²⁺ ions have been identified as the preferred adsorption sites. Adsorption energies, geometries and electron densities have been evaluated. Their dependence on the interlayer distance has been considered for investigating the behaviour of the AFM with microfabricated silicon lever in the pressure region of 10^-8 N. The AFM topographical images are strongly dependent on the chemical nature of the tip.