ELECTRON-CAPTURE AND TRANSFER IONIZATION IN COLLISIONS OF FAST H+ ANDHE2+ IONS WITH CU ATOMS

One-electron capture involving either simple charge transfer or transf er ionization leading to the formation of Cu-q+ ions for q = 1-5 has b een studied for H+-Cu collisions in the energy range 70-720 keV amu(-1 ). Both one- and two-electron capture by He2+ ions leading to Cu-q+ io ns for q = 1-7 and q = 2-5 in the ranges 35-360 keV amu(-1) and 35-150 keV amu(-1) respectively have been determined. A crossed beam coincid ence counting technique has been used to measure cross sections for ea ch of these processes corresponding to particular values of q. In the case of H+-Cu collisions, measured fractions of Cu-q+ ions formed in p articular states of q have also been satisfactorily described in terms of an independent electron model with electron removal from either th e 4s or 3d subshells. Comparisons between the present cross sections f or H+ and He2+ impact have also been made with the corresponding value s previously measured for iron.