Electron, Positron and Photon Collisions with Atoms and Molecules

Electron-ion recombination

Electron recombination with multicharged ions such as Au25+ or U28+, has been regarded as a puzzle for a number of years, due to very high recombination rates and lack of clear resonance structure. Based on the ideas of many-body quantum chaos [V. V. Flambaum, A. A. Gribakina, G. F. Gribakin, and M. G. Kozlov, "Structure of compound states in the chaotic spectrum of the Ce atom: localization properties, matrix elements, and enhancement of weak perturbations", Phys. Rev. A 50, 267 (1994)], a statistical theory of electron recombination with complex ions has been developed [V. V. Flambaum, A. A. Gribakina, G. F. Gribakin, and C. Harabati, "Electron recombination with multicharged ions via chaotic many-electron states", Phys. Rev. A 66, 012713 (2002)]. Its main assumptions and the properties of chaotic many-electron states have been tested and verified in numerical calculations of the Au24+ compound ion [G. F. Gribakin and S. Sahoo, "Mixing of dielectronic and multiply-excited states in electron-ion recombination: a study of Au24+", J. Phys. B 36, 3349 (2003)]. In addition with have identified and examined another recombination mechanism due to target ion polarization by the incident electron [A. V. Korol, G. F. Gribakin and F. J. Currell, "Effect of target polarization in electron-ion recombination", Phys. Rev. Lett. 97, 223201 (2006)]. In most cases stidied this mechanism leads to a systematic enhancement of the recombination rate in the energy ranges void of dielectronic resonance, which is usually assumed to be described by simple radiative recombination.

We have also proposed that electron-ion recombination can be used to study the parity nonconservation due to the fundamental electron-nucleus weak forces in elelctron collisions, and estimated the size of this effect for highly-charged hydrogen-like ions [G. F. Gribakin, F. J. Currell, M. G. Kozlov and A. I. Mikhailov, "Parity nonconservation in electron recombination of multiply charged ions", Phys. Rev. A 72, 032109 (2005)].