Recombination of Au25+ with free electrons at very low energies

Recombination of Au25+ ions with free electrons has been investigated in a merged-beams experiment at the UNILAC of GSI in Darmstadt. Special emphasis was put on the recombination at very low energies in the electron-ion centre-of-mass frame. At E-rel = 0 eV we found an enormous recombination rate exceeding the theoretical expectations for radiative recombination by a factor of 365. For further investigation of this enhancement, the electron density and the magnetic field guiding the electron beam were varied. While an increase of the electron density by a factor of 10 had little influence, the measured rate coefficient increased significantly with the magnetic field strength.