Controlled formation of weakly bound atomic negative ions by electron transfer from state-selected Rydberg atoms
Fachbereich Physik der Universität, D-67653 Kaiserslautern, Germany
2 Laboratoire de Physique des Lasers, Université Paris-Nord, F-93430 Villetaneuse, France
3 Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588-0111, USA
Accepted: 4 September 1997
Using crossed atomic beams and mass spectrometric ion detection we have studied the formation of negative Ca ions in slow collisions between laser-excited state-selected and Rydberg atoms and ground state Ca atoms. The rate coefficients exhibit resonant behaviour with maxima at an effective principal quantum number n* of about 11.5 and an estimated peak value of about . Two different theoretical calculations, based on a curve-crossing model and on a modified adiabatic theory, respectively, yield n*-dependences of the rate coefficients in good agreement with the experimental results.
PACS: 34.70.+e – Charge transfer / 32.10.Hq – Ionization potentials, electron affinities / 41.75.Cn – Negative-ion beams
© EDP Sciences, 1997