Comparative Analysis of the Efficiency of Different Photoabsorption Channels of NeAr+ Molecular Ions Associated with Transitions to the ArNe+ State

Abstract

The processes of continuous photoabsorption by weakly bound NeAr⁺ molecular ions at room and elevated temperatures have been theoretically investigated. A comparative analysis of the relative contributions of four types of phototransitions (photodissociation, bound-bound transitions, free-free transitions and photoassociation) with different initial and final states of internuclear motion to the total absorption coefficient at room and elevated temperatures was made. It is shown that it is possible to describe under certain assumptions the above contributions under quasi-equilibrium conditions without resorting to direct calculation of photoabsorption coefficients for each of the channels. It is demonstrated that the relative efficiencies of different types of phototransitions in the NeAr⁺ ion radically differ from previous results for homonuclear noble gas ions and for ArXe⁺ and KrXe⁺ ions. The dependences of these contributions on the wavelength of the incident radiation and on the gas temperature of the plasma were investigated. It was found that there are well-defined regions corresponding to the predominance of a particular channel of phototransitions within the wavelength range where efficient absorption occurs. The presented results are of interest for the construction of kinetic models of pumping and excitation relaxation in gas lasers based on active media containing Ne/Ar mixtures.