The profile reflects the physical properties of the plasma: the Doppler and electronic contributions can be at the center of the line while the ionic effect is on the wings. The analysis of the electronic contribution is necessary for precise spectroscopic observations and can also provide useful indications and information on the conditions and concentrations in the plasma. In this work, we have developed an estimate of the relativistic contribution of binary ion-electron collisions in the width of isolated lines, where the fine structure of the emitting ion is neglected. We have calculated the amplitude of relativistic electron operator of the dipolar radiation of an ion immersed in plasma, within the framework of the impact approximation and the semi-classical approximation. In this operator's calculation we used a new effective potential. This potential is considered to include both the diffraction (quantum) and the screening field effect. The amplitude of the relativistic collision operator is developed for Hydrogenic ion lines in plasma and compared with Alexiou’s result which taking into account the Coulomb interaction between the emitting ion and the perturbed electron.

relativistic collision operator; hydrogen ions; electron scattering cross-sections.