Visible Continua in Xenon, Krypton, and Neon

Abstract

An investigation of the continua (2900–7000 Å) radiated from positive columns in xenon, krypton, and neon is described for discharges in the pressure range of 5 to 40 torr (neon, 20 to 120 torr) and current range of 0.7 to 5 mA, conditions chosen for normal glow, unconstricted discharges. Experimental results show definitely that these continua are not attributable to free—bound, free—free transitions and indicate that they are of molecular origin, the radiating states being populated by electron excitation of metastable molecules formed by three-body conversion of metastable atoms.