The introduction of gases like nitrogen or neon for cooling the edge region of magnetically confined fusion plasmas has triggered a renewed interest in state selective cross sections necessary for plasma diagnostics by means of charge exchange recombination spectroscopy. To improve the quality of spectroscopic data analysis, charge exchange and ionisation cross sections for N 7+ + H(n = 1, 2) have been calculated using two different theoretical approaches, namely the atomic-orbital closecoupling method and the classical trajectory Monte Carlo method. Total and state resolved charge exchange cross sections are analysed in detail.In the second part, we compare two collision systems involving equally charged ions, C 6+ and N 6+ on atomic hydrogen. The analysis of the data lead to the conclusion that deviations between these two impurity ions are practically negligible. This finding is very helpful when calculating cross sections for collision systems with heavier not completely stripped impurity ions.

Abstract. Charge exchange in Be4+ -H(n = 1, 2) collisions was studied using the atomic-orbital close-coupling formalism in its impact parameter description and applying electron translational factors. Calculations were carried out in the energy range of 1 − 750 keV/amu with fully stripped beryllium ions impacting on atomic hydrogen in its ground state (1s) and in the excited n = 2 states. An optimized description of both collision centres was determined by analyzing the convergence of the total cross sections and also by comparison with other theoretical approaches. This optimized description consists of up to 170 basis states involving hydrogen-like states and pseudostates. We present total, n-resolved as well as n -resolved cross sections. The latter are needed to evaluate the emission cross sections in two limiting collisional plasma environments, i.e. single-collisional and multi-collisional. The calculated emission cross sections are compared with experimental data from the fusion experiment JET. Taking the experimental environment and certain characteristics of the theoretical methods into account, the agreement can be considered to be quite good.

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Electronic excitation and charge transfer processes in collisions between Mg (3 1 S 0 ) atoms and Rb + ( 1 S 0 ) ions in the 0.07-4.00 keV energy range