Datensatz

Zusammenfassung

We tested and applied a laser-induced oxidation method for identifying the IR-active stretching mode absorptions of linear C_2n+1 molecules which have known strong UV-vis absorptions. For this purpose, we trapped the molecules of carbon vapor in non-inert matrices (pure O₂ and Ar-O₂ mixtures) at temperatures providing molecular growth. The matrix was exposed to laser light tuned to the wavelength of the UV-vis transition of a specific carbon species. We observed a bleaching of that UV-vis absorption and a correlated decrease of lines in the IR spectra for C₉, C₁₁, C₁₃, C₁₅, and C₂₁. The data suggest that the strongest IR absorptions of the C_2n+1 (n≧4) chains form a regular pattern with increasing n. To obtain information about IR absorptions of carbon chain oxides, oxygen matrices with replaced ¹⁶O -> ¹⁸O isotopes were applied. Our data revise some of the IR assignments existing in the literature.