Search

We report the results of theoretical studies of radiative processes involving heteronuclear rare gas ions formed in low-temperature plasmas of noble gas mixtures. The continuous absorption of light by such molecular and quasimolecular ions occurs as a result of a number of nonadiabatic bound–bound, bound–free, free–free, and free–bound transitions between their ground and excited electronic terms. The main emphasis in the work is put on the development of a self-consistent semiclassical theory of such processes, taking into account the contributions of all rovibrational levels and continuum states of such ions. Our approach is based on the theory of nonadiabatic transitions between potential energy curves of diatomic molecules combined with the approximation of a quasicontinuum for their rovibrational levels. Nonadiabatic free–free and free–bound transitions in asymmetric collisions of heavy rare gas atomic ions with atoms of a buffer rare gas are described in a similar way. We use analytical formulas derived in this work to carry out calculations of the continuous absorption processes involving ArXe+ and KrXe+ ions with sufficiently low and moderate dissociation energies ( D 0 ArXe + = 184 meV and D 0 KrXe + = 396 meV). The competition of different reaction channels in the total absorption coefficient is discussed. The results obtained demonstrate importance of studied radiative processes in the formation of continuous absorption of electromagnetic radiation in plasmas of noble gas mixtures. [ABSTRACT FROM AUTHOR]