Vibrational spectra ethyne

S.F. Parker, P.H. Dallin, B.T. Keiller, C.E. Anson U.A. Jayasooriya (1999). Phys. Chem. Chem. Phys., 1,2589-2592. An inelastic neutron scattering study and re-assignment of the vibrational spectrum of [Os3(CO)9(p,2 CO)(ji3 tl C2H2)], a model compound for chemisorbed ethyne. 

Exercise 27-9 The photoelectron spectrum of ethyne in Figure 27-10 shows vibrational fine structure for the carbon-carbon bond in ionization at about 18.5 eV with spacings of about 0.27 eV. Explain how one could decide whether the observed vibrational spacings are more associated with the ionized excited state of ethyne rather than the ground state. Review Section 9-7B. 

The ligand-model vibrational spectroscopy approach has contributed strongly to fairly reliable identifications on metal surfaces of C2 species of the types 1, 2 (ethene type II spectra) (17), 3 (ethene type I spectra), 4 (ethene type I spectra), 8, and 13 (ethyne type B spectra) as well as to possible identifications of types 5, 7, 15 (ethyne type A spectra), 16, and 20. Approximate band positions and associated intensity distributions in the spectra from normal and perdeutero species should be considered together (/ 7). The correspondence of the infrared spectrum from 4 with type I spectra is less satisfactory for the C2D4 ligand than in most other cases. However an extra structural variable in this case is the degree of nonplanarity of the cyclic C2M2 skeleton, which may differ between the model compound and the surface species. 

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