Abstract
The optical attenuation method (OAM) developed recently by Matsumoto et al. (1980) has been extended to photon emission in the VUV spectral region to investigate initial- to final-state selective electron capture in Ne2+-Xe collisions at 40 keV. One-electron-capture cross sections for Ne2+ ions in their 3P ground state were found to be only one half of that for the metastable 1D ions which is explained by a larger contribution from transfer ionisation for the latter. With these results initial- to final-state selective excitation cross sections for the most important electron capture channels were derived and found to be consistent with the corresponding total one-electron-capture cross section.