SIMBAD references

This paper compares laboratory gas-phase spectra of neutral and cationic linear carbon-chain radicals with astronomical diffuse interstellar band (DIB) spectra. The origin bands of the strong electronic transitions of the studied species, C_2nH (n=3-6), HC_2nH⁺ (n=2-4), NC_2n–2N⁺ (n=3, 4), do not coincide with detectable DIBs, except for HC_2n–1N⁺ (n=3), which possibly matches a weak feature. It is concluded that the column densities of these species through the observed diffuse clouds are below 2x10¹² cm^–2. The profile change and the shift of the maxima of the absorption bands with temperature are illustrated. The relation to radio-astronomical detection of carbon chains in diffuse media is also discussed.