Recent measurements of radiation from certain rare gas–halogen mixtures have indicated the efficient production of broadband emitters in the visible. This paper reports a gain measurment at 4416 A˚ in mixtures containing the two emitters tentatively identified as Kr2F* (&lgr;max=4000 A˚ and FWHM=900 A˚ and ArXeF* (&lgr;max=4600 A˚ and FWHM=900 A˚). Attenuation of the 4416‐A˚ probe laser during electron‐beam and electron‐beam‐sustained discharge excitation of 2–3 atm pressure mixtures of argon‐krypton‐fluorine and argon‐xenon‐fluorine indicates absorption only. The fluorescence signals from ArXeF* and XeF* (Ar/Xe/F2mixture), and KrF* and Kr2F* (Ar/Kr/F2mixtures) were monitored simultaneously with the absorption of the probe laser. Since the absorption was not proportional to the fluorescence of these species, it is tentatively concluded that it is due to another transient species. Typical absorptions of 10−3cm−1were observed at pump levels of 105W cm−3. A knowledge of the absorption mechanism will be required to assess the efficiency with which such lasers can be made to operate, if at all.