Experimental study of electron transfer in multiply charged iron-ion collisions with atomic hydrogen

The measurement of electron-transfer cross sections sigma in ion collisions with atomic hydrogen has been extended to iron ions with mass number A = 56, charges q between +4 and +13, and specific energies E/A between 27 and 290 keV/amu. The charge-state dependences of sigma range from q/sup 1.5/ at lower values of q and E to q/sup 3/ for higher values of these quantities. An empirical scaling relationship is found for converting H/sup +/+H cross sections into those for Fe/sup q/ + H. Several effects correlated with shell structure in the incident ion are observed. Our results are not explained by presently available theoretical calculations.