Theoretical effect of various broadening parameters on ultraviolet line profiles

The relative importance of various damping parameters in ultraviolet lines under conditions of normal stellar atmospheres are studied. It is found that the damping by electron collisions is always much smaller than either the radiative or the classical damping, except for lines that arise from high excitation levels and do not therefore develop strong damping wings. A damping constant equal to 10 times the classical value is always much too large when compared to the more realistic (electron + radiative) damping.