Light emission from heteronuclear Ar-Kr doubly ionized excimer molecules

Light emission from a  ~100 mbar Ar-Kr mixture excited by a pulsed discharge is described. The discharge was arranged to form a homogeneous cathode layer and spatial filtering was used to measure time-dependent spectra emitted from a region where electrons accelerated in the cathode sheath induce the light emission. Novel excimer bands were observed around a wavelength of 315 nm in addition to the better known so called third excimer continua of Ar and Kr. A tentative assignment for these bands to charge-transfer transitions: ArKr2+ →  Kr+ +  Ar+ + hν is provided and discussed in the context of earlier works on heteronuclear ionic excimer molecules. Predictions for the wavelength positions of similar emission bands are provided for other combinations of noble gases. The rate constants for the formation of heteronuclear ArKr2+ excimers in three-body reactions and two-body collisional quenching of Kr2+∗ ions by Ar atoms have been determined from the time dependence of the ArKr2+ emission