Excitation by electron capture in collisions of ground state and metastable Ne2+with Xe at 40 keV

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 Ne 2+ -Xe collisions at 40 keV. One-electron-capture cross sections for Ne 2+ ions in their 3 P ground state were found to be only one half of that for the metastable 1 D 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.