2000A&A...354.1062V

We investigate the consequences on hydrocarbon chemistry in diffuse and translucent clouds of including an interaction between gaseous C⁺ ions and dust grains. In general, we find that models in which much of the carbon is deposited and retained on grain surfaces within the cloud lifetime represent a poor match to observations. Conversely, models in which carbon is efficiently converted to methane generally provide satisfactory agreement with the observed chemistry of translucent clouds. Such models also predict that the hydrocarbons C₂H, C₃ H₂ and H₂CO may be detectable in diffuse clouds.