ELECTRONIC ABSORPTION-SPECTRA OF LINEAR CARBON CHAINS IN NEON MATRICES .4. C-2N-7(1 N=2)

The (1) Sigma(u)(+) <-- X (1) Sigma(g)(+) electronic absorption system of the carbon chains C-2n+1 (n=3-7) trapped in 5 K neon matrices has been identified. The (1) Pi(u) <-- X (1) Sigma(g)(+) transition has al so been observed for C-5 and C-7, as well as a dipole forbidden one fo r all the species. The spectroscopic information was derived from abso rption spectra recorded after neutralization of mass-selected anions a nd cations that were codeposited with an excess of neon to form a matr ix. The assignment is based on the mass-selection, theoretical predict ions, and trends observed for this homologous series. These results ar e 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. (C) 1996 America n Institute of Physics.