Benzene adsorption on nickel (100) and (111) faces studied by leed and high resolution electron energy loss spectroscopy

Abstract

Studies of benzene (C 6H 6 and C 6D 6) adsorption have been performed by high resolution electron energy loss spectroscopy (HRELS) and LEED experiments on nickel (100) and (111) single crystal faces at room temperature. Chemisorption induces ordered structures, c(4 × 4) on Ni(100) and (2√3 × 2√3)R30° on Ni(111), and typical energy loss spectra with 4 loss peaks accurately identified with the strongest infrared vibration bands of the gazeous molecules. Benzene chemisorption preserves the aromatic character of the molecule and involves respectively 8 nickel surface atoms on the (100) face and 12 on the (111) face by adsorbed molecule. The interaction takes place via the π electrons of the ring. Significant shifts of the CHτ bending and CH stretching vibrations show a weakening of the CH bonds due to the formation of the chemisorption bond and a coupling of H atoms with the nickel substrate.