Emission spectra of heteronuclear diatomic rare gas positive ions

Abstract

An electric discharge in a binary mixture of rare gases produces several discrete emission band groups confined to a narrow wavelength region characteristic of the pair of rare gases and closely related in energy to the ionization energy difference between the two atoms. Such spectra were observed for nine of the ten binary mixtures of He, Ne, Ar, Kr, and Xe. The energy differences between band groups of a given mixture agree closely with the doublet splittings of the lowest states of the atomic ions. The suggestion is offered that the emission spectrum is carried by the heteronuclear ion (XY)+ which undergoes a bound–bound charge–transfer transition X+Y →XY++hν, in which X is the lighter and Y the heavier element in the mixture.

Interactions of rare gas cations with lighter rare gas atoms

“…8,9 Excitation by electron beams produced similar emissions. 10,11,12 Tanaka et al 13 were the first to suggest that these emissions might be due to electronic transitions within RG + -RG′ ions, and they produced emission spectra of the ten possible pairs of species for RG + , RG′ = He-Xe by electric discharge.…”

Emission of Ionic Molecules (KrXe)+ on Excitation by a Hard Ionizer

“…While in a low-pressure plasma in an electric discharge in paired mixtures of inert gases up to five such bands are observed [3], in a mixture under a mean or high pressure excited by ionizing radiation there are no transitions from the levels corresponding to the states of the atomic ions 2 P 3/2 [4][5][6]. In view of the high selectivity of excitation, emission of heteronuclear ionic molecules of inert gases is of interest for direct transformation of nuclear energy into coherent and incoherent optical radiation [6][7][8].…”

“…The molecular bands observed in the spectra of emission of paired mixtures of inert gases [1, 2] have been identified [3] as transitions between the states of heteronuclear ionic molecules:…”

Interaction potentials, spectroscopy and transport properties of RG+–He (RG=Ar–Rn)

“…An early report of spectra by Tanaka et al 3 was extended by Dabrowski, Herzberg and Yoshino (DHY), 4 who published a detailed UV absorption spectroscopic study of the Ar + -He complex. Since the ground state of Ar + is 2 P, interaction with He gives 2 Π and 2 Σ + electronic states in the absence of spin-orbit coupling, with the latter state expected to be lower in energy owing to less electron repulsion along the internuclear axis.…”

“…Early experimental work comprises the UV emission spectra from Tanaka et al 3 where the assignment was only tentative, and scattering studies of He + and Kr by Weise. 22 The transport studies of Saito et al 5 23 , where spin-orbit coupling was included using basis sets of approximately double-ζ quality.…”