Abstract
Phase-changing broadening constants of the line of Xe I at lambda =3.51 mu m are obtained by analysing Voigt profiles recorded by using a linear-absorption laser experiment. He, Ne, Ar, Kr and Xe perturbers are considered. Measurements made with He and Xe perturbers differ significantly from those obtained by use of saturated-absorption techniques. A variation of the Doppler width is observed at low pressures of Xe, probably caused by non-resonant excitation transfers from highly populated levels of Xe towards the upper level of the transition.