TRANSIENT MOLECULAR-ION FORMATION IN RYDBERG-ELECTRON CAPTURE

Resonance structure has been observed in total cross sections for the capture of an electron from a Rydberg-state atom by a singly charged p rojectile with speed v(ion) comparable to the Bohr velocity v(e) of th e target electron. Prominent peaks in the data at reduced velocities ( v) over tilde = v(ion)/v(e) = 0.8 and 0.5 result from two distinct cap ture mechanisms in which the target electron passes once or three time s, respectively, through the midplane between the nuclei. The three-sw ap peak at (v) over tilde = 0.5 marks the high-velocity limit of molec ular-ion formation in which the electron is shared between the two cha rge centers. This result illustrates that new paradigms for collision dynamics may emerge when reactions are examined at or near the corresp ondence principle limit.