Position of the σ-shape and π resonances of C2H2, C2H4 and C2H6 on Cu(100) at 60 K: A NEXAFS study

Geometric structure and chemical bonding of acetylene adsorbed on Cu(110)

“…This distortion agrees well with the distortion of the geometry experimentally found by X-ray absorption spectroscopy (XAS) [4] indicating a deformation of the molecules. Similar bond elongations were found with PED for acetylene adsorbed on Pd(1 1 1) (1.34 ± 0.1 Å ) [10], Ni(1 1 1) (1.44 ± 0.15 Å ) [2,3,11] and with XAS for acetylene adsorbed on Cu(1 0 0) [7,12] and Ni(1 1 0) [13]. On Cu(1 1 0) a low-symmetry site for the adsorption has been proposed from a combined Hartree-Fock, angleresolved ultraviolet photoemission spectroscopy (ARUPS) and vibrational spectroscopy study [8].…”

“…Previous investigations [12,36] have correlated the position of the shape resonance with changes in C-C bond length in an empirical approach denoted ''Bond-length with a ruler''. Using this simple picture, the position of the shape resonance of around 297 eV for both species would indicate a C-C bond elongation from 1.21 Å of the free acetylene to around 1.35 Å for the adsorbed molecule.…”

Density functional theory study of surface catalysis and adsorption on several elements in Group I-B and VIII

“…E ad = −2.70 eV by LDA and -1.09 eV by GGA. The optimized tilting angle of the C-H bonds to the surface and the lengthening of the C-C bond are in good agreement with near-edge X-ray adsorption fine structure data [145,146] and previous calculations [147]. The vibrational frequencies of C 2 H 2 /Cu(001) are calculated in the harmonic approximation, assuming the displacement fields to be strictly localized to an H(D) atom [110] directions of Cu (110), since the unit cell of the (110) surface is a rectangle.…”

Infrared Reflection−Absorption Spectra of C2H4 and C2H6 on Cu: Effect of Surface Roughness

“…As demonstrated by near edge X-ray absorption fine structure (NEXAFS) spectroscopy, C 2 H 4 adsorbs with the molecular plane parallel to the Cu(100) 28 and Cu(111) 29 planes. On Cu(110), it adsorbs on the ridges, with the molecular plane parallel to the surface, as can be inferred from scanning tunneling microscopy, 30 combined photoemission and photoelectron emission, 31 and X-ray absorption and emission spectroscopy.…”