Study of the electron-ion recombination processes in the xenon afterglow plasma

The electron-ion recombination mechanisms of Xe+ and Xe2+ ions were studied in pure xenon by means of the stationary afterglow method. The time dependence of the electron density was determined by measuring the shift of the resonant frequency of the cavity containing the plasma. The time variation of the number of atoms created by recombination mechanisms in the various excited levels of xenon was measured by observation of the intensity of the xenon lines emitted in the afterglow. The studies established that the recombination of the atomic ions, Xe+, populates all excited levels of xenon, while the dissociative recombination of the molecular ions, Xe2+, populates only the levels situated below the minimum of the potential curve of Xe2+. The simultaneous study of the electron density and the 6872 A line intensity in the afterglow shows that when the electron density is lower than 109cm-3, the electron-Xe+ recombination is a two-body recombination involving only one electron. An upper limit of 10-9 cm3 s-1 has been determined for the recombination coefficient for this type of recombination. (author)