Electronic absorption spectra of linear carbon chains in neon matrices. IV. C2<i>n</i>+1 <i>n</i>=2–7

Abstract

The 1Σ+u←X 1Σ+g electronic absorption system of the carbon chains C2n+1 (n=3–7) trapped in 5 K neon matrices has been identified. The 1Πu←X 1Σ+g transition has also been observed for C5 and C7, as well as a dipole forbidden one for all the species. The spectroscopic information was derived from absorption spectra recorded after neutralization of mass-selected anions and cations that were codeposited with an excess of neon to form a matrix. The assignment is based on the mass-selection, theoretical predictions, and trends observed for this homologous series. These results are related to published absorption spectra of graphite vapor trapped in rare gas matrices. The suggestion that such species may be potential carriers of diffuse interstellar bands is considered.