A spectral line shape code using the "quasimolecular model" has been developped for dense and hot plasmas. First this alternative treatment is justified. Then the importance of using a two-centre basis and the effects of the plasma screening are discriminated. Specific hydrogen-like and helium-like transitions are studied for the exhibition of dense plasma effects(PPS, asymmetries, satellite features) and for a comparison with experimental results. It is shown that satellites due to extrema are enhanced by the ion dynamics correction.