Abstract The near-infrared emission spectra were studied for xenon diluted with krypton, argon, and neon, respectively, in order to estimate the origin of an emission band at 1260 nm which was previously observed at several hundred Torr(1 Torr=133.2 Pa) of pure Xe irradiated with pulses of high-energy electrons. A continuous band around 1260 nm was observed only in Xe-Ar mixtures. This band appeared at Xe pressures above 20 Torr(diluted in 600 Torr of Ar) while it was detected above 190 Torr in pure Xe. In Xe–Ar mixtures, three emission lines due to Xe 5d(3/2)1 were also observed at 1700, 2020, and 2650 nm. On the basis of the reported kinetic data for the reactions of rare gas mixtures, the present results led to the conclusion that the band at 1260 nm was due to emission from highly excited excimer states, of which the dissociation limits were higher Rydberg states above the energy level of the Xe2+ ion.