Laser-induced charge transfer in the CH6+ quasimolecule

Abstract

The charge transfer cross section is calculated for C 6 + + CH(ls) collisions, through photon assisted 5gO transitions. The theory developed by Copeland and Tang, and ourselves, is employed, and the validity of the approximations used is tested. The four processes considered have widely different characteristics with regards to the laser wavelength needed, the collision dynamics and the applicability of back-of-the-envelope estimates based on the Landau-Zener approximation. We point out the relevance of those processes to the impurity diagnostics of magnetically confined fusion plasmas and to the development of short wavelength lasers.

Laser-Field Induced Modifications of Electron-Transfer Processes in Xe+–N2 Collision

“…Absorption of a transfer laser photon is a switch that governs the energy flow from Xe + to N 2 . It is a single-photon absorption process; thus, at the unsaturated region the cross section will rise as the laser power density increases linearly. − I N + +N 2 + / I Xe + as a function of laser intensity in the interaction region is shown in Figure . The conversion ratio I N + +N 2 + / I Xe + increases linearly with increased laser intensity, i.e., the cross section rises as the laser power density increases linearly.…”

“…LICT calculations have been performed on simple systems: a completely stripped ion and a hydrogen atom (C 6+ + H + + ℏω 12 ), He 2+ + H + ℏω, 13 or two alkali elements (K + + Na + ℏω 14 ) in the case of the weak-field limit, for which laser coupling can be regarded as a perturbation. In the slow-collision regime, the process is described in the molecular-state scheme and the reliability of different approximations is checked including that of the useful Landau−Zener model.…”