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XPS studies of the adsorption of CH3CN and C6H5CN on the Ni(111) surface

1986; Elsevier BV; Volume: 176; Issue: 1-2 Linguagem: Inglês

10.1016/0039-6028(86)90162-7

1879-2758

Kosaku Kishi, Yoshikazu Okino, Yoshihito Fujimoto,

Semiconductor materials and devices

Adsorption of CH3CN and C6H5CN on the Ni(111) surface has been studied by XPS as a function of the substrate temperature. At 150 K the CH3CN molecule strongly rehybridized to chemisorb on Ni(111) by di-σ bonds with carbon and nitrogen atoms. The chemisorbed species, , gave a C1s peak at 284.6 eV and an N1s peak at 397.7 eV, showing large shifts, −2.3 and −2.5 eV, from those of condensed CH3CN. Small amounts of CH3CN persisted up to 270 K as the species bonding through nitrogen lone-pair electrons. The species gave a C1s peak at ≈ 286.0 eV and an N1s peak at 399.6 eV. The C6H5CN molecule chemisorbed on Ni(111) at 220 K by rehybridizing the nitrile group but not with the aromatic ring. The chemisorbed species, , gave a Cls peak at 284.5 eV and an N1s peak at 397.7 eV, being shifted by −1.4 and −2.5 eV from those of condensed C6H5CN. In both cases with CHP3CN and C6H5CN compounds of very low vapor pressure were formed probably by polymerization of the molecules at the position of the nitrile group when multi-layers of the nitriles condensed at 150 K were irradiated by an X-ray source for 1 h.