SURFACE-STRUCTURE AND REACTIVITY OF AROMATIC-MOLECULES - CAN WE TRACK DOWN TRENDS IN THE PERIODIC-TABLE

The adsorption characteristics of benzene on transition-metal surfaces as a prototype molecule for aromatic systems are investigated to search for trends across the periodic table. Data on adsorbate structure and orientation, intramolecular structure, and molecular stability are collected and discussed comparatively. The strength of benzene-metal surface interactions increases in going from the right to the left in the periodic table and thus follows the general trend of chemical reactivity. However, the second period seems to behave exceptionally, in that remarkable molecular stability is encountered on these surfaces. The details of the surface chemical bond of aromatic molecules are still poorly understood, and the need for more rigorous theoretical treatment is emphasized.