Broadening and shifts of the xenon line atλ=3.51μm: Measurements and theoretical interpretation

Broadening and shifts of the Xe I line at $\lambda =3.51\mathrm{}$ μm are measured at two temperatures and for various perturbers, He, Ne, Ar, and Xe, by use of a laser linear-absorption experiment. A theoretical interpretation is proposed which involves the quantum theory of collisions. The long-range part of the interaction potential is described by the successive orders of the multipole expansion of the interaction between excited-state atoms and ground-state perturbers; the short-range part is described by an extension of a Fermi-type potential, and a cutoff function is used for the intermediate case. For all perturbers, calculated broadenings and shifts are shown to be sensitive to the position of the potential well, but not to its depth.