Energy-gain spectroscopy measurements of single-electron capture by Ar6+in Ne and Ar

State-selective absolute capture cross sections sigma n,l for Ar 6+ on neon and argon have been measured in the velocity interval from 0.01 to 0.03 au. Only reaction channels corresponding to curve crossings between 5 and 15 au approximately are found to be important. In contrast to findings at higher velocities, the summed cross sections sigma n and sigma tot increase strongly with velocity. Some special features of the partial cross sections are discussed.