Surface vibrations and the nature of the adsorption state: CH on Pt(111).

Molecular vibrations of CH and CD adsorbed on Pt(111) at 140 K and ∼300K have been measured by high resolution electron energy loss spectroscopy. The comparison of CH and CD spectra allows an unambiguous assignment of the observed losses to the excitation of C−H bending, C−H stretching, and C−C stretching modes of nondissociatively adsorbed acetylene. From the relative intensities of losses the hybridisation state is determined to be near sp . The C−C stretching frequency indicates a C−C bond order of ∼1.8. [ABSTRACT FROM AUTHOR]