The effect of charge exchange reaction on carbon lines

The effect of charge exchange reactions: carbon ions with neutral hydrogen and carbon ions with neutral helium, on carbon ionization equations is analysed. Both, optically thin and optically thick, photoionization models for the line emission region of QSOs are considered. From the computed line intensities it is suggested that the charge exchange mechanism should be included in future models.Partially supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil.