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Abstract:
In this thesis multiphoton ionization of molecular hydrogen is investigated
by using 50 fs laser pulses with 400 nm central wavelength and a Cold Target Recoil Ion
Momentum Spectrometer (COLTRIMS), known as Reaction Microscope (ReMi). It was
found that singly excited Rydberg states play a dominant role in the bound ionization
process. In order to examine the importance of these Rydberg states for the dissociative
ionization, the electron nuclear correlation and electron emission asymmetry was studied
experimentally and theoretically. The kinetic energy distribution of the ions is simulated
by numerically solving the time-dependent Schrödinger equation, whereas the electron
localization asymmetry is modeled with a semiclassical theory. The presented findings
indicate that dissociation via the H+2
1sσg state is much less pronounced than commonly
believed. Singly-excited Rydberg states are found to play the most important role
in multiphoton bound and dissociative ionization of molecular hydrogen with 400 nm
photons.
The second part of the thesis reports about a pump-probe measurement using a pulse
shaper setup in 4f geometry. To our knowledge this is the first report about combining a
pulse shaper with a ReMi. The experimental data is compared to a former pump-probe
measurement that uses a Mach-Zehnder interferometer to confirm the correct operation
of the pulse shaper.
