Hannover 2003 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
MO: Molekülphysik
MO 9: Ultraschnelle Elektronendynamik
MO 9.2: Talk
Thursday, March 27, 2003, 14:15–14:30, B 302
Changes of the Electronic Structure along the Internuclear Coordinate: The Na2 21Σu+ double minimum state — •Oksana Bazhan, Matthias Wollenhaupt, Andreas Assion, Christian Horn, Dirk Liese, Andreas Präkelt, Christian Sarpe-Tudoran, and Thomas Baumert — Universität Kassel, Fachbereich Physik, Heinrich-Plett-Str. 40, D-34132 Kassel
Quantum control over chemical reactions can be obtained employing various so-called one parameter schemes. An important aspect in quantum control is introduced by nonadiabatic coupling of the potential curves involved in the time evolution of a quantum system. Electronic changes along the internuclear coordinate are predicted for the 21Σu+ double minimum potential well in the Na2 molecule. In our experiment measurements of kinetic photoelectrons using time-of-flight spectrometry (TOF) combined with a femtosecond multiphoton ionisation pump-probe technique in a molecular beam allow to probe the change of the electronic structure along the internuclear coordinate. The Na2 21Σu+ double minimum state is excited via a 340 nm (40 fs FWHM) laser pulse. Thereby a vibrational wavepacket slightly above the barrier is created. A second 267 nm pulse ionizes the molecule. According to calculations the change of electronic structure near the avoided crossing at 4.7 Å leads to photoionization probabilities rapidly changing with geometry. Experiments related to the change of the photoionization probability as a function of the internuclear distance are presented.