Universal formula for the spectral line profile

A universal formula is derived for the spectral line profile of atoms. It describes the whole spectrum, including collisional, intermediate, and quasistatic frequency ranges in the case when optical collisions take place with impurity particles in a strong electromagnetic field which influences the collision dynamics. A new physical effect is predicted: it is manifested by a dependence of the collisional shift of an absorption (stimulated emission) line profile on the intensity of an electromagnetic field.