Single-electron capture into C3+(n,l) subshells in C4+-Li collisions (20-80 keV)

Abstract

Absolute emission cross sections have been measured for 29 lines of the C IV spectrum in the wavelength range 20-500 nm resulting from C4+-Li collisions at impact energies between 0.83 and 6.67 keV amu-1. From these emission cross sections one-electron capture cross sections sigma nl have been deduced for all subshells with n<or=7, using known transition probabilities. It is found that electron capture takes dominantly into the n=5 shell, as expected from a classical model. Capture into the n=6,7 shells increases with increasing impact energy, whereas capture into the n=5 shell decreases slightly, resulting in a total capture cross section of about 2*10-14 cm2 which is almost independent of energy. The distributions over l subshells within each n shell are strongly energy dependent, shifting to larger values of l with increasing energy. However, capture into the 5g subshell is dominant over the whole energy range. The results are partly explained qualitatively and are in good agreement with very recent calculations by Fritsch and Lin (1983) who used a modified two-centre atomic orbital expansion.