Single-molecular diffusivity and long jumps of large organic molecules

The work Single-molecular diffusivity and long jumps of large organic molecules: CoPc on Ag(100) (by: Agata Sabik, John Ellis, Holly Hedgeland, David J. Ward, Andrew P. Jardine, William Allison, Grażyna Antczak, Anton Tamtögl) is about diffusion of phthalocyanine molecules with cobalt (CoPc) over Ag(100) surface. Experimental studies were performed over a wide temperature range of 200 to 500 K using a unique Helium Spin-Echo Spectroscopy technique based on the scattering of helium atoms.

The analysis of experimental results was supported by modeling using Molecular Dynamics. In this paper, basic diffusion parameters such as activation energy and diffusion coefficient were determined. From the analysis of the distribution of molecular jump lengths, it can be seen that the movement of CoPc along the Ag(100) surface is carried out by both single and long jumps.

Figure 1 A Geometry of adsorption of CoPc molecule on Ag(100) surface; B Illustration of Helium Spin-Echo Spectroscopy method.