Guided ion beam studies of electron and isotope transfer in N-14(+)+N-15(2) collisions

Collisions of ground state N+ ions with N-2 were investigated in a Guided I on Beam (GIB) apparatus at center-of-mass (CM) collision energies up to 10 eV. Isotopic labeling of the target gas, N-15(2), was used as one criterion to distinguish electron transfer, atom transfer, and isotope exchange chan nels. The absolute cross sections are in good agreement with previous measu rements. By combining the GIB technique with time-of-flight analysis (acron ym GIB-TOF) more detailed information on the reaction dynamics has been obt ained. The product velocity distributions measured for N-15(2)+ and (NN+)-N -14-N-15 indicate that both, electron and atom transfer, have to be divided into at least two parts, a direct one and one which seems to be characteri stic for a long lived complex. The branching ratios derived for these four channels show a strong energy dependence. The mean product kinetic energy i ndicates that the remaining nitrogen atom is most probably formed in the me tastable N(D-2) state. For the nearly thermoneutral N-14(+)-N-15(+) isotope exchange it was observed that a significant fraction of the translational energy is transferred into internal excitation of the neutral molecule. (C) 2000 American Institute of Physics. [S0021-9606(00)00616-4].