Thomas-Fermi theory of multiple ionization
Main investigator: M. Brewczyk (University of Bialystok, Poland)
Molecular multiple ionization is studied using a hydrodynamic model which allows one to deal with many-electron systems in intense laser fields. The predicted kinetic energy releases of the fragmentation channels are in good agreement with the measured energies in CO2 and N2O.
Ph. Hering, Thèse de doctorat, Paris (1999)
Ph. Hering, M. Brewczyk, and C. Cornaggia, Phys. Rev. Lett. 85, 2288 (2000)
Electronic states of multicharged molecular ions
Main investigator: Ph. Millié and V. Brenner (Laboratoire Francis Perrin, Saclay, France)
The energies of the electronic states of molecular multicharged ions are calculated using ab initio complete active self-consistent field - complete active space second order perturbation theory (CASSCF/CASPT2) theory calculations.
L. Quaglia et al., J. Phys. B : At. Mol. Opt. Phys. 35, L145 (2002)
Quantum theory of single and multiple ionization
Main investigators: E. Charron et al. (Laboratoire de Photophysique Moléculaire, Université Paris Sud, Orsay, France)
A time-dependent wavepacket approach is developed for the ultrafast electronic and nuclear dynamics of the laser-induced double ionization of H2. In particular the nuclear dynamics is treated on a full quantum level in order to go beyond the usual Born-Oppenheimer fixed-nuclei approximation.
S. Saugout, C. Cornaggia, A. Suzor-Weiner, and E. Charron, Phys. Rev. Lett 98, 253003 (2007)
S. Saugout, E. Charron, and C. Cornaggia, Phys. Rev. A 77, 023404 (2008)
Ultrafast tunnel and multiphoton ionization of H2
Main investigators: J. Posthumus, X. Urbain et al. (Laboratoire de Physique Atomique et Moléculaire, Université Catholique de Louvain, Belgique)
The vibrational population of the H2+ molecular ion following tunnel ionization of H2 was unknown. A strong departure is observed from the usually assumed Franck-Condon distribution using a 790-nm excitation scheme. This result has been confirmed by new tunnel calculations which take into account the rapid variation of the ionization rate with the internuclear distance. This important advance was made possible by the powerful transportable set-up developed at Louvain. The multiphoton regime is investigated using the 3rd harmonic of the laser at 263 nm. AC Stark shifted multiphoton resonances are shown to dominate the molecular dynamics and in particular the final vibrational distribution of the molecular ion.
X. Urbain et al., Phys. Rev. Lett. 92, 163004 (2004)
J.H. Posthumus, B. Fabre, C. Cornaggia, N. de Ruette, and X. Urbain, Phys. Rev. Lett. 101, 233004 (2008)
Femtosecond spectroscopic study of carminic acid-DNA interaction
Main investigators: C. Kryschi et al. ( Friedrich-Alexander-Universität Erlangen-Nürnberg, Deutschland), Th. Gustavsson (Laboratoire Francis Perrin, Saclay, France), and S. Pommeret (Service de Chimie Moléculaire, Saclay, France)
Photo-excited carminic acid and carminic acid-DNA complexes in a buffer solution at pH7 has been investigated using femtosecond resolved fluorescence upconversion and transient absorption spectroscopy.
R. Comanici et al., Chem. Phys. 325, 509 (2006)
Multiphoton ionization and dissociation of small molecules
Main investigators: D. Dowek et al (Laboratoire des Collisions Atomiques et Moléculaires, Université Paris Sud, Orsay, France)
A complete three-dimensional analysis of the ionization of NO2 and CF3I has been performed at 400 nm and 266 nm using the powerful "Corrélations Vectorielles" experiment developed at Laboratoire des Collisions Atomiques et Moléculaires. These first experiments will be continued using the PLFA laser facility.