4. Outlook - control of the Na3** collision complex
Upon achievement of the desired energy resolution of the ion imaging, it will be implemented to study the mechanisms of the DCT process (2). In fact, the Na2(v") + Na**(nl) collisions leading to the formation of a highly excited complex is an interesting process to study due to various ionisation channels through which the complex can decay:
Threshold energy [eV]
Na2 (X 1Sg+ ,v??) + Na** (nl)
Na- + Na+ + Na
Na2 + Na++ e-
Na2++ Na + e-
Na2- + Na+
Na2++ Na -
The threshold energies are given in terms of total (electronic, vibrational, and rotational) energy deposited in the Na2 + Na colliding system. Besides the manipulation of the ionisation channels by control of the electronic and vibrational excitation of atoms and molecules, also schemes for coherent laser control are thinkable.
1. M. Keil, T. Kolling, K. Bergmann, and W. Meyer, "Dissociative attachment of low-energy electrons to vibrationally excited Na2 molecules using a photoelectron source", Eur. Phys. J. D 7, 55 (1999).
2. J. Bömmels, E. Leber, A. Goplan, J. M. Weber, S. Barsotti, M.-W. Ruf, and H. Hotop, "Energy broadening due to photo-ion space-charge in a high resolution lasre photoelectron source" (in preparation).
4. O. Kaufmann, A. Ekers, C. Gebauer-Rochholz, K.U. Mettendorf, M. Keil, and K. Bergmann, "Dissociative charge transfer from highly excited Na Rydberg atoms to vibrationally excited Na2 molecules", Int. J. Mass Spectrom. 205, 233 (2001).
8. A. Ekers, O. Kaufmann, M. Keil, and K. Bergmann, "Associative ionization in collisions of electronically excited Na atoms with vibrationally excited Na2(v") molecules", Eur. Phys. J. D 7, 65 (1999).
10. A. T. J. B. Eppink and D. H. Parker, "Velocity map imaging of ions and electrons using electrostatic lense: Application in photoelectron and photofragment ion imaging of molecular oxygen", Rev. Sci. Instrum. 68, 3477 (1997).