120kev Ar8+-li Collisions Studied By Near Uv And Visible Photon Spectroscopy

A spectroscopic analysis of light emitted in the 200-600 nm wavelength range by Ar ⁷⁺ , Ar ⁶⁺ and Ar ⁵⁺ ions after charge exchange in 120keV Ar ⁸⁺ -Li collisions is performed. Transitions with Δn = 1 and Δn = 2 for n = 8, 9, 10 and 11 states of Ar8 following single electron capture are identified and the production cross sections for n = 8 and n = 9 are deduced from emission cross sections and compared with those calculated by the three-body classical trajectory Monte-Carlo method. Lines due to double capture process were observed and identified as Rydberg transitions 3snl-3sn'l' (n = 7, 8 and 9) in Ar VII. Lines due to triple electron capture process were found and identified as transitions 3s ² nl-3s ² n'ï and 3s3pnl- 3s3pril'(n = 7, 8) in Ar VI. The configurations produced during the collision provides evidence that electron-electron interaction play an important role in double and triple charge exchange processes. © 1993 IOP Publishing Ltd.