Abstract
The influence of the foreign gases hydrogen, helium, nitrogen, and argon on the selective reflection from mercury vapor at 2537 Å was studied at pressures up to 1500 atm. The results were interpreted on the basis of the classical theory of reflection from an absorbing medium. The damping constant was found to vary linearly with foreign gas density as predicted by collision broadening theory. Frequency shifts and collision diameters determined from selective reflection data agree fairly well with values measured in absorption by other workers.