C. Trump

Multiphoton ionization and dissociation of

We investigate multiphoton ionization (MPI) of at 532 nm excitation wavelength in an intensity range of -. We find strong fragmentation of the molecule with formation of , , , and as charged dissociation products. Photoelectron spectra show that the charged products originate in photodissociation of . Ionic dissociation starts after excitation of to the state and probably high vibrational levels of the bending mode in . Symmetric is significantly less probable than asymmetric dissociation. MPI of mainly populates ionic X (000) and (100) vibronic states below light intensity. At high intensity also B vibronic states seem to become directly populated with rising probability. All lowest-order MPI electron groups are accompanied by at least one above-threshold ionization group. A sensitive dependence of the photoelectron spectra on light intensity may point to bond-angle softening of low-lying X vibronic states of which is expected to be brought about by a favourable resonant one-photon coupling between the X and A electronic states.

Non-sequential double ionization of Ne in intense laser pulses: a coincidence experiment

The dynamics of Neon double ionization by 25 fs, 1.0 PW/cm 2 laser pulses at 795 nm has been studied in a many particle coincidence experiment. The momentum vectors of all ejected atomic fragments (electrons and ions) have been measured using combined electron and recoil-ion momentum spectroscopy. Electron emission spectra for double and single ionization will be discussed. In both processes the mean electron energies differ considerably and high energetic electrons with energies of more than 120 eV have been observed for double ionization. The experimental results are in qualitative agreement with the rescattering model.