Evidence for electron correlation during double capture in fast ( v∼10 a.u.) collisions

Two-electron capture involving simultaneous transfer of an electron to the continuum (or to a Rydberg state) and a bound state has been investigated for collisions of 3.5 MeV/u Ne¹⁰⁺ with He, Ne, and Ar targets. The extent of this double capture to nonequivalent electron configurations is found to exceed expectations of the independent-particle model suggesting that electron correlation may contribute significantly to two-electron capture even in fast (v~10 a.u.) collisions.