Electron-correlation effects in double-electron-capture collisions of 60-keV C6+ with He

The method of zero-degree Auger spectroscopy was used to measure cross sections for the production of K and L Auger electrons by double electron capture in 60-keV ${\mathrm{C}}^{6+}$+He collisions. Corresponding atomic-structure calculations were performed to determine the related Auger and x-ray transition rates. The resulting Auger yields are found to deviate significantly from unity. The Auger yields were applied to evaluate cross sections for the production of the configuration 3lnl' (n=3 to 5) and 2lnl' (n=3 to 8). These data are found to compare well with experimental results obtained previously for the isocharged system ${\mathrm{O}}^{6+}$+He. Comparison is also made with recent calculations including the electron-electron interaction. It is shown that electron-correlation effects play a significant role for double electron capture in the studied collision system.