KINEMATIC ISOTOPE EFFECTS IN LOW-ENERGY-ELECTRON CAPTURE

The replacement of hydrogen with its isotope deuterium, in collisions with multiply charged ions, is shown to lead to a suppression of total charge transfer cross sections at collision energies much higher than previously thought. We demonstrate, using a fully quantal calculation of electron capture in collisions of N4+(2s) with H(1s) and D(1s), th at this isotope effect is significant for capture into the N3+(3d) sta tes at collision energies approaching 10 eV/amu. Estimates of the magn itude of the effect, using the semiclassical Landau-Zener-Stueckelberg model, are made for several multiply charged systems.