Abstract
The adsorption states and diffusion processes of NO molecules on Pt(997) at low coverage were investigated by using infrared reflection absorption spectroscopy (IRAS), scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. When NO molecules adsorb on the surface, each molecule transiently migrates on the surface from the first impact point to a possible adsorption site at low temperature (11 K). There are four stable adsorption sites for NO on Pt(997); the bridge site of the upper step, the fcc and hcp-hollow sites of the terrace, the on-top site of the terrace and the fcc-hollow site of the lower step. At higher temperature above 45 K, NO molecules start to diffuse thermally to more stable adsorption sites, and finally they are trapped at the bridge sites of the step which are the most stable adsorption sites among the four sites.
