Continuum Electron Production in Mev Collisions of Krypton Ions with Krypton and Xenon Targets

The impact-parameter dependence for the emission of continuum electrons following MeV collisions of Kr ions with Kr and Xe atoms has been measured for a range of collision energies from 0.1 to 3.2 MeV and scattered-ion angles from 3(DEGREES) to 12(DEGREES). The electron spectra exhibit a continuum of energies which are not characteristic of the atomic states of Kr and Xe. The energies and impact parameter dependence of these electron emissions show them to be consistent with the promotion of M- and N- shell electrons. For Kr('+) - Kr collisions the coincidence data show thresholds for the production of electrons at distances of closest approach of 0.7 a.u. and 0.45 a.u. Similar thresholds are seen for Kr('+) - Xe collisions at 0.6 a.u. and 0.35 a.u. These data suggest that electron promotion via a number of molecular orbitals interacting at a common R(,0) is responsible for the electron continuum. This interpretation is in contrast to that of Afrosimov and Gordeev and coworkers, who conclude that for the Kr - Kr system the continuum electrons result from the filling of a single vacancy from a well-defined molecular orbital.